Vo Thi Lan Huong : Morphological and physico‐mechanical properties of finished cotton fabric by regenerated Bombyx mori silk fibroin
Figure 4. Reaction scheme for fibroin regeneration
3.3. Silk fibroin fixation on cotton fabric
To observe the fibroin regeneration onto the cotton fabric, SEM measurements have
been performed. The SEM images of untreated cotton fabric and representative samples
after deposition of fibroin were shown in Figure 5. Figure 5a‐c shown the micro‐morphology
of untreated cotton samples with different magnification. The images clearly revealed a
plain weave structure of the fabric, and a specific microstructure of cotton fiber. After
padding the cotton fabric with the silk fibroin solution and regenerating fibroin to solid
stage, the treated cotton fibers were covered by a layer of the regenerated silk fibroin, Figure
5d‐f. It should be note that the coagulated fibroin films deposited onto surface of cotton
fibers were uniform, and they did not fill in the space between the fibers.
(a) Co (50) (b) Co (1000) (c) Co (3000)
(d) CoReS3 (50) (e) CoReS3 (1000) (f) CoReS3 (3000)
Figure 5. SEM image of the cotton samples: (a, b, c) Untreated cotton fabric with
magnification of 50, 1000 and 3000, respectively; (d, e, f) Treated cotton fabric with 1.5
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Vo Thi Lan Huong : Morphological and physico‐mechanical properties of finished cotton fabric by regenerated Bombyx mori silk fibroin
wt% fibroin (CoReS3) with magnification of 50, 1000 and 3000, respectively.
In order to evaluate the influence of regenerated fibroin to the color of the treated cotton
fabric, the color of the untreated cotton fabric and treated fabric with fibroin were measured
according to the CIELAB color scale relative to the standard illuminant D65.
Table 2 showed the difference values of ∆L*, ∆a*, ∆b* and ∆E the samples before and
after treatment with the silk fibroin. The negative values of ∆L* and ∆a*, and positive value
of ∆b* indicated that the treated sample were slightly darker, greener and yellower than
original cotton fabric. However, these absolute values were small, and the color‐difference
value of ∆E was less than 1.0 confirming no color change of the treated cotton fabric. It is
difficult to distinguish the color‐difference of the fabric samples before and after treatment by
naked eyes. The results could open a potential application of this technique for
functionalizing textile materials due to no color change of final products.
Table 2. Color measurement comparison of selected samples
Sample ∆L* ∆a* ∆b* ∆E
Untreated cotton fabric ‐1,40 ‐0,05 0,15 0,53
Treated cotton fabric (CoReS3)
3.4. Physico‐mechanical properties of cotton fabric treated with silk fibroin
The formation of a silk fibroin layer on cotton fibers would change the physical and
mechanical properties of the fabric. To confirm this assumption, several analytical testes
including air permeability, wrinkle recovery angle and breaking strength were carried out.
As shown in Figure 6a, the air permeability of untreated and treated cotton fabrics were
not change and its values were around 98 to 99 l/m2.s. The air permeability values were
unchanged due to silk fibroin only covering the cotton fibers. This assumption was
correlated with the observations of SEM images.
The wrinkle recovery angle of untreated and treated cotton fabrics were presented in
Figure 6b. It is clearly observed that the values of wrinkle recovery angle of all cotton
samples were not high, meaning low crease recovery ability. However, the crease recovery
ability had been slightly improved by increasing concentration of fibroin solution (from 0.5
to 1.5 wt%).
The breaking strength of untreated and treated cotton fabrics were illustrated in Figure
6c. The breaking strength values of the untreated cotton in warp and weft directions were
482.85 N and 287.85 N, correspondingly. There were an insignificant decrease in the
breaking strength of CoReS1, CoReS2 samples by approximately 3% and 10% in warp and
weft directions, respectively. However, the breaking strength of the treated fabric with high
concentration of silk fibroin solution (1.5 wt%) was increase. This could be due to the fibroin
layer deposited on cotton fibers leading to restriction of fiber mobility, and thus result in
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increasing the breaking strength.
100
Air permeability (l/m2.s)80
Breaking strength (N)
60
40
20
0 CoReS1 CoReS2 CoReS3
Co (a)
500 Warp direction (b)
Weft direction
400
300
200
100
0 CoReS1 CoReS2 CoReS3
Co (c)
Figure 6. (a) Air permeability, (b) Wrinkle recovery angle and (c) Breaking strength of untreated and
treated cotton fabrics.
4. Conclusions
Degummed silk was effectively dissolved by aqueous LiEtW system with enhanced
dissolution rate which was significantly shorter than that in the conventional method. The
fibroin solution was dissolved from degummed silk could be used to form fibroin coatings
on cotton fabric using the pad‐dry‐cure technique. In addition, a following acetone and
aluminum sulfate treatment was introduced to regenerate silk fibroin. The presence of silk
fibroin on the cotton fabric was confirmed by SEM, physical and mechanical testes. The silk
fibroin concentration in the solutions affected the physico‐mechanical properties of treated
cotton fabric. Higher silk fibroin concentration improved the wrinkle recovery angle and
breaking strength values of the samples, but insignificantly affected to the air permeability
of the treated fabrics. This investigated method would bring new perspectives in application
of regenerated silk fibroin on textile materials.
Acknowledgments: The authors would like to thank the staffs of School of Textile ‐ Leather
and Fashion, Hanoi University of Science and Technology for their technical support on this
research. We thank Hanoi Industrial Textile Garment University for financial support under
grant number 1901/2019HĐ.NCKH.
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Vo Thi Lan Huong : Morphological and physico‐mechanical properties of finished cotton fabric by regenerated Bombyx mori silk fibroin
Author Contributions: Nguyen, N.T conceived and designed the experiments; Vo,T.L.H and
Duong, T.T performed the experiments; Nguyen, N.T and Vo,T.L.H analyzed the data and wrote the
paper.
Conflicts of Interest: The authors declare no conflict of interest.
References
1. Chen, X., Knight, D. P., Shao, Z., & Vollrath, F. 2001. Regenerated Bombyx silk solutions studied with
rheometry and FTIR. Polymer, 42(25), 09969‐09974.
2. Tan, L.Y., Sin, L.T., Bee, S.T., Ratnam, C.T., Woo, K.K., Tee, T.T. and Rahmat, A.R., 2019. A review of
antimicrobial fabric containing nanostructures metal‐based compound. Journal of Vinyl and Additive
Technology, 25(S1), E3‐E27.
3. Chen, X., Li, W., Zhong, W., Lu, Y., & Yu, T. 1997. pH sensitivity and ion sensitivity of hydrogels based
on complex‐forming chitosan/silk fibroin interpenetrating polymer network. Journal of Applied
Polymer Science, 65(11), 2257‐2262.
4. Mandal, B. B., Grinberg, A., Gil, E. S., Panilaitis, B., & Kaplan, D. L. (2012). High‐strength silk protein
scaffolds for bone repair. Proceedings of the National Academy of Sciences, 109(20), 7699‐7704.
5. Kundu, B., Rajkhowa, R., Kundu, S.C. and Wang, X., 2013. Silk fibroin biomaterials for tissue
regenerations. Advanced drug delivery reviews, 65(4), 457‐470.
6. Liu, T.L., Miao, J.C., Sheng, W.H., Xie, Y.F., Huang, Q., Shan, Y.B. and Yang, J.C., 2010.
Cytocompatibility of regenerated silk fibroin film: a medical biomaterial applicable to wound
healing. Journal of Zhejiang University SCIENCE B, 11(1), 10‐16.
7. Zhu, Z., Ling, S., Yeo, J., Zhao, S., Tozzi, L., Buehler, M.J., Omenetto, F., Li, C. and Kaplan, D.L., 2018.
High‐Strength, Durable All‐Silk Fibroin Hydrogels with Versatile Processability toward
Multifunctional Applications. Advanced Functional Materials, 28(10), p.1704757.
8. Yan, Y., Cheng, B., Chen, K., Cui, W., Qi, J., Li, X., & Deng, L. (2019). Enhanced Osteogenesis of Bone
Marrow‐Derived Mesenchymal Stem Cells by a Functionalized Silk Fibroin Hydrogel for Bone Defect
Repair. Advanced healthcare materials, 8(3), 1801043.
9. Ngo, H. T., & Bechtold, T. (2016). Sorption behavior of reactive dyed labelled fibroin on fibrous
substrates. Journal of Applied Polymer Science, 133(35).
10. Ngo, H. T., & Bechtold, T. (2017). Surface modification of textile material through deposition of
regenerated silk fibroin. Journal of Applied Polymer Science, 134(29), 45098.
11. Motta, A., Fambri, L., & Migliaresi, C. (2002). Regenerated silk fibroin films: thermal and dynamic
mechanical analysis. Macromolecular Chemistry and Physics, 203(10‐11), 1658‐1665.
12. Matsumoto, K., Uejima, H., Iwasaki, T., Sano, Y. and Sumino, H., 1996. Studies on regenerated protein
fibers. III. Production of regenerated silk fibroin fiber by the self‐dialyzing wet spinning method.
Journal of Applied Polymer Science, 60(4),503‐511.
13. Sashina, E.S., Bochek, A.M., Novoselov, N.P. and Kirichenko, D.A., 2006. Structure and solubility of
natural silk fibroin. Russian journal of applied chemistry, 79(6), 869‐876.
14. Kosawatnakul, S., Nakpathom, M., Bechtold, T. and Aldred, A.K., 2018. Chemical finishing of cotton
fabric with silk fibroin and its properties. Cellulose Chemistry and Technology, 52(1‐2), 123‐128.
ISBN : 978-623-91916-0-3 93
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Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
Optically Responsive Textile Application Based on
Uniaxially Ordered Polymer-Liquid Crystal
Microfibers
Rusliana Fatayati1, Ahmad Kusumaatmaja and Yusril Yusuf2
1,2Department of Physics, Faculty of Mathematics and Natural Science,
Universitas Gadjah Mada, Sekip Utara BLS 21 Yogyakarta 55281, Indonesia
* Correspondence: [email protected] , [email protected]
Abstract: This study discusses the fabrication and characterization of optically responsive microfibers
with uniaxially ordered liquid crystal molecules at their core. The liquid crystal microfibers were
electrospun from a solution of PVP (polyvinylpyrrolidone) and MBBA (N-(4-Methoxybenzylidene)-4-
butylaniline) using absolute alcohol as a solvent. Two parallel copper (Cu) collectors were used to
obtain ordered fibers. The microfibers with oriented LC were well fabricated at a voltage of 5 kV; the
distance between the needle and the collectors was 10 cm. The light intensity that passed through the
LC microfibers depended on the diameter of the needle and the PVP concentration during the
electrospinning process. A thermal-optical analysis revealed that the fibers were responsive to
temperature. The rise of temperature resulted in a dark pattern of the fibers under a polarized optical
microscope (POM) while the fibers were re-shined as the temperature was lowered. A DSC
measurement confirmed that the LC molecules were confined in the fibers.
Keywords: Composite microfibers; liquid crystal microfibers; responsive fibers
ISBN : 978-623-91916-0-3
1. Introduction
Liquid crystal is a material that can be combined with many types of polymer. Many
applications of liquid crystal have been demonstrated using a fabricated polymer liquid crystal
composite [1–3]. Research of polymer liquid crystal composite is interesting because of the unique
characteristics of liquid crystal itself. Liquid crystal molecules have a positional order similar to the
positional order of molecules in solids, but the molecules can move freely similar to molecules in
liquids. Therefore, although the molecules in liquid crystal form a liquid, they result in a
birefringence phenomenon similar to the molecules in anisotropic crystals. The most interesting
property of liquid crystal is the crystal's ability to respond to stimuli, such as external fields, lights,
and temperatures. Polymers are primarily used as matrices due to their dominant volume fractions.
To obtain more potential applications, further studies have been done in combination of two
different scientific topics. They took the advantages offered by electrospinning technology and liquid
crystal. Krause et al, successfully fabricated liquid crystal fibers from Main Chain Liquid Crystal
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Rusliana Fatayati: Optically Responsive Textile Application Based on Uniaxially Ordered Polymer-Liquid Crystal Microfibers
Elastomer (MCLCE) through the process of electrospinning and crosslinking. Thin films were
produced which were first oriented and then crosslinked by UV light to give liquid single crystal
main- chain elastomers. These elastomers show exceptional mechanical properties such as strong
load-dependent thermoelastic effect and a nonlinear stress–strain relation. In their mechanical
properties, they resemble spider silk [4]. In other approaches, the electrospinning of liquid crystal-
polymer fibers was demonstrated with the use of coaxial electrospinning [5] and non-coaxial
electrospinning method to keep the liquid crystal of 5CB phase-separated and self-assembled as a
nematic core within a polymer shell [6]. Furthermore, liquid crystal microfibers responded optically
to temperature changes [7].
Kim et al, in their review, reported that liquid crystal functionalization of electrospun
polymer fibers has potential applications, especially in wearable technology, such as smart textile or
fibers integration with sensors [8]. In this study, we demonstrated the fabrication of polymer-liquid
crystal fibers as optically responsive fibers. The fibers were electrospun by non-coaxial
electrospinning and we used the same polymer as that had been demonstrated before [6], PVP is a
linear polymer and transparent so it has no birefringent. A linear polymer can make liquid crystal
molecules easier to be aligned. Liquid crystal of MBBA was mixed directly with polymer solution.
Because of their potentials, the investigation focused on other physical properties. We applied heat to
the fiber and analyzed the effect of temperature change on the morphology or optical appearance of
the fiber.
2. Materials and Methods
Materials
The polymer used in the study was PVP. It had a molecular weight of 1,300,000 g mole–1 and,
was purchased from Sigma-Aldrich Corporation in Singapore. The study also used absolute ethanol
as a polymer solvent; it was obtained from Merck, Indonesia. Nematic MBBA LC was used; it had a
molecular weight of 67.37 g mole–1, and it was provided by the Tokyo Chemical Industry
Corporation, Limited in Japan.
Electrospinning Method
The electrospinning process was adapted by recent study [7]. First, the polymer solution was
prepared by dissolving PVP in absolute ethanol using hot plate stirrer at room temperature for 2
hours. The concentration of PVP was 17 %. Second, the PVP solution was then mixed with MBBA
using hot plate stirrer at room temperature for one day. The concentration of MBBA in PVP solution
was 3:2 of PVP/MBBA mass ratio.
The microfiber was prepared using the electrospinning method. An electrospinning
apparatus was set up where high voltages were 5 kV and 10 kV and the distance between the needle
and collectors was 10 cm. The aligned fibers were obtained by modifying the collectors. The collectors
were two-dimensional (2D) modified Cu; each measured 7.9 × 1.5 × 0.15 cm, and the gap was 2 cm. A
glass substrate measuring 1 cm × 2.5 cm was put between the collectors, as shown in Fig. 1. The
needle's internal diameter (ID) was 0.5 mm and 0.8 mm. Glass slides measuring 10 mm × 25 mm were
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placed between the two collectors. The electrospinning process was performed for 10 s.
Figure 1. Electrospinning set-up using parallel copper collectors with gap 4.8 cm
Characterization and Measurements
Optic characterization of liquid crystal microfibers were carried out as follows. The sample
was put under a crossed polarizer to observe the optical behavior of liquid crystal microfibers. The
observation was conducted using a polarized optical microscope (Nikon, Optiphot-pol) by varying
the rotation angles from 0º to 360º. Images of the sample were taken using Pixel View program. The
transmitted intensity of light, I, was measured using a photo detector.
To characterize the alignment of fibers, the fiber orientation order parameter was determined
to S [9]. The order parameter S could also determine the degree of order in nematic liquid crystal [10].
The S value varies from 0 indicating random alignment for fiber and isotropic phase for liquid crystal
to 1 as a perfect alignment and perfect orientation order of nematic phase. The order parameter S is
formulated as;
= (3cos − 1) (1)
where is either the angle between the individual fiber forms with preferred alignment director or
the angle between each molecule of nematic liquid crystal and the direction of nematic axis n. The
angle of fiber was measured using imageJ software.
The optical behavior of liquid crystal microfibers as well as optical behavior of planar nematic
liquid crystal was described by [10]. The transmitted light intensity was given by Equation (2, 3).
Liquid crystal microfibers were aligned planar to the plane of P/A or in other words = 90°, thus =
. The maximum intensity at = 45° and the minimum intensity at = 0° or multiple angle of 90°.
=2 (2)
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Rusliana Fatayati: Optically Responsive Textile Application Based on Uniaxially Ordered Polymer-Liquid Crystal Microfibers (3)
=
where is the light intensity after the polarizer, is the angle between optic axis and
analyzer/polarizer and is the phase difference.
Thermal-optical transmittance measurements of the samples were carried out as follows. Two
indium tin oxide (ITO) coated glasses as substrates were used to make a sample cell separated by two
parallel strips of Mylar spacer with 50 µm thickness, one layer of ITO glass consisting of polymer-
liquid crystal fiber that had been collected before. This cell construction aims to keep the thermal
condition around the fibers stable. A heater control unit (Digital Controlled CHINO DB500) was used
as a heat source. The cell was put into an enclosed hot plate that could gain heat by inducing electric
field. The sample was heated from a room temperature around 25°C to 35°C as an isotropic phase for
liquid crystal, then was cooled back to room temperature again. A photodetector was used to
measure the intensity of fibers, and the fibers were observed by polarized optical microscope (Nikon,
Optiphot-pol). The thermal properties of the sample were analyzed using DSC. A DSC-60 Plus from
the Shimadzu Corporation in Japan was used. Temperatures ranged from -10ºC–60ºC; the heating rate
was 10ºC every minute, and it was maintained using a nitrogen flow of 30 ml every minute.
3. Results and Discussion
3.1 Optic Behavior of Liquid Crystal Microfibers
Uniaxially oriented polymer-liquid crystal microfibers with diameter under 6 µm were
successfully fabricated using the modified electrospinning as shown in Fig. 2. Two copper (Cu) gap
collectors were applied to draw uniaxially aligned fibers. The liquid crystal microfibers were
uniaxially aligned across the gap with their longitudinal axes oriented perpendicular to the edges of
the gap. Figure 2 shows the difference between microfibers with liquid crystal and only pure PVP
observed under cross polarizer. In Fig. 2(a), the x-axis light passing from polarizer (P) is converted to
elliptically polarized light by liquid crystal molecules inside microfibers, therefore the polarized light
direction can pass the analyzer (A). While pure PVP (Fig. 2(b)) cannot convert the polarized light,
causing the light unable to pass the analyzer. Also, the liquid crystal microfibers in Fig. 2(a) shows a
positive birefringence presented by liquid crystal molecules in the fiber as had been described in a
recent study [7]. The modified collector of electrospinning system successfully delivered a good value
of orientation order parameter + ∆ = 0.990 ± 0.014.
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(c)
25
d = (4.26)m
20
Frequency (%) 15
10
5
0 4 6
2 diameter size (µm)
Figure 2. Uniaxially aligned microfiber of (a) liquid crystal inside the PVP microfiber rotated at 45 ºC
and (b) pure PVP at 0º under crossed polarizers; polarizer (P) and analyzer (A), and (c) diameter
distribution of liquid crystal microfibers
Polarized optical microscope (POM) also showed another unique optical phenomenon
exhibited by varying rotation angle of the fibers. In Fig. 3(c), the dark pattern appeared when the
sample of PVP-MBBA fiber is in position 0° to the polarizer or analyzer and the bright pattern was
seen in fibers when the sample was rotated at 45° with respect to polarizer and analyzer in Fig. 3(d).
Meanwhile, the sample of PVP fiber only showed the dark pattern in Fig. 3(a) and Fig. 3(b). Optical
measurement on the fibers aims to measure the intensity of light passing through fibers to every
turning angle change. As shown in Fig. 3(e), we can see that the intensity remained low at every angle
in PVP fiber. This happened because the PVP fiber could not convert the polarized light coming from
polarizer, hence it was blocked by the analyzer, while the liquid crystal microfibers displayed a
change in intensity. The intensity graph in Fig 3(f) showed a sinusoidal pattern similar to the pattern
that appears when polarized light is converted to elliptically polarized light with a component that
can pass through the crossed polarizer. Therefore, the maximum intensities occurred when the liquid
crystal microfibers were rotated to 45º with respect to the polarizer and analyzer. This result was
confirmed by Eq. (2); the sin2 (2 ) was equal to 1, so the maximum light intensity was able to pass
through the sample. Rotating the sample so that it was parallel to either the polarizer or the analyzer
resulted in minimum light intensities. Additionally, the needle's diameter was an important
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parameter. Using a needle with a 0.8 mm ID, the fibers were brighter than the fibers yielded using a
needle with a 0.5 mm ID.
It can be concluded that the drawing conditions on the fibers alignments affected the
transmitted light-intensity magnitude. With randomly oriented liquid crystal microfibers, fibers
parallel to the polarizer were possible; thus, the light intensity decreased. Meanwhile, the uniaxially
aligned LC microfibers, which were rotated to 45º with respect to the polarizer and the analyzer,
clearly had a maximum transmitted light intensity.
Figure 3. PVP fiber at 0° (a) and 45° (b), and PVP-MBBA fiber at 0° (c) and 45° (d) with respect to P
and A (c). The black dot represents light intensity of PVP fiber (e) and the black line represents light
intensity of PVP-MBBA fiber (f).
3.2. The thermal behaviors of liquid crystal microfibers
The liquid crystal microfibers nematic and isotropic phase transitions underwent an
endothermic process. In Fig. 4, the first curve describes the liquid crystal transition from crystal phase
to the nematic phase and the second curve describes the liquid crystal transition from the nematic
phase to the isotropic phase. A DSC measurement of pure MBBA resulted in a nematic-isotropic
transition temperature (TNI) at about 47.7ºC, as shown in Fig. 4(a). The second curve in Fig. 4(a) shows
isothermal phase transitions starting at 47.7ºC; the transitions indicate the LC molecules began
transitioning from the nematic phase to the isotropic phase (the value of TNI).
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0
0
-5 -1
Heat flow (mW)
Heat flow (mW)-10
-2
-15
-20 -10 0 10 20 30 40 50 60 70 -10 0 10 20 30 40 50 60
exo up
exo up Temperature (C)
Temperature (C)
(b)
(a)
Figure 4. The DSC measurements of (a) pure MBBA (b) and LC microfibers.
The DSC of the liquid crystal microfibers is shown in Fig 4(b). This DSC result focusses on
observing the behavior liquid crystal inside the fibers. The TNI of the liquid crystal was observed at
about 36ºC, which is much lower than TNI of pure MBBA. The small size of fibers greatly disrupted the
long range orientational order of liquid crystal molecules and the addition of polymer (PVP) caused
the intermolecular force between liquid crystal molecules to decrease, making them easier or faster to
undergo of transition from nematic to isotropic phase. A previous study explained that the TNI of
MBBA could be influenced by the addition of other material types [11]. This analysis was confirmed
by enthalpy changes in the nematic-isotropic phase. PVP is an amorphous polymer, so it caused the
enthalpy to decrease, as shown in Fig. 4. The enthalpy in liquid crystal microfibers nematic-isotropic
phase was lower than the enthalpy in pure MBBA's nematic-isotropic phase.
700 heating 7.0
650 cooling 6.5
Transmitted Light Intensity (a.u)600 6.0
550 5.5
Diameter (m)5005.0
450 4.5
400 28 30 32 34 36 4.0 28 30 32 34 36
350
300 Temperature (C) 26 Temperature (C)
26
Figure 5. Temperature effect on transmitted intensity (a) and (b) on diameter of PVP-MBBA fiber.
The phase transitions of liquid crystal microfibers were also confirmed by thermal-optical
measurement. A photodetector was used to observe the heating and cooling of the sample. As shown
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in Figure 5(a), heating the sample decreased the light intensity of the fibers (dark pattern) due to the
phase transition from nematic phase to isotropic phase. It means, as the temperature rose, the
molecules which were uniaxially aligned along the fibers got oriented randomly. Hence, they could
not transmit the light through the analyzer. While cooling the sample from the temperature of
isotropic phase to nematic phase increase the light intensity (bright pattern). The result of thermal-
optical measurement had been reported before on a recent study [Rusliana]. The morphology showed
that a temperature change did not affect the fibers' diameters, as shown in Fig 5(b), and this was most
likely due to the high melting temperature of the PVP. The results indicate that liquid crystal
microfibers have a strong potential to be used as smart-textile components. For example, the fibers
can be used as body-temperature sensors in integrated textiles.
4. Conclusions
Optically responsive liquid crystal microfibers were successfully fabricated using non-coaxial
electrospinning. Uniaxally oriented LC microfibers were obtained with modified Cu collectors, a high
voltage of 5kV and a polymer with a high molecular weight. A POM analysis showed that the
samples had unique optical behaviors. The fibers maximum intensities occurred when the fibers were
aligned uniaxially and rotated to 45º from the polarizer and analyzer. A thermal-optical analysis
showed the fibers responded to temperature stimuli. A DSC measurement confirmed that the LC
molecules were confined when using the PVP as a polymer matrix. Adding the amorphous polymer
changed the TNI and decreased the enthalpy in the nematic-isotropic phase. The liquid crystal
microfibers can be used as body-temperature sensors in integrated textiles. This is because the human
body does not emit high temperature; it only emits between the fibers nematic- and isotropic-phase
temperatures.
Acknowledgments
This study was supported by grants from the WCR and the PMDSU Programs. The authors
are grateful for financial support from the Republic of Indonesia's Ministry of Research, Technology
and Higher Education.
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7. Fatayati, R.; Kusumaatmaja, A.; Yusuf, Y. Thermal-optical analysis of polymer-liquid crystal microfibers.
Jpn. J. Appl. Phys. 2018, 57, pp. 4–6, 10.7567/JJAP.57.088005
8. Kim, D.K.; Hwang, M.; Lagerwall, J.P.F. Liquid crystal functionalization of electrospun polymer fibers. J.
Polym. Sci. Part B Polym. Phys. 2013, 51, 855–867, 10.1002/polb.23285
9. Dersch, R.; Liu, T.; Schaper, A.K.; Greiner, A.; Wendorff, J.H. Electrospun Nanofibers : Internal Structure
and Intrinsic. J. Polym. Sci. Part A Polym Chem. 2002, 41, 545–553, 10.1002/pola.10609
10. De Gennes, P. G., and Prost, J., 1993, The physics of Liquid Crystals, 2nd ed.; J. Birman, S. F. Edwards, C. H.
Llewellyn, Smith, M. Rees; Clarendon Press: Oxford, 1993.
11. Konrad, R.; Schneider, G. M. Nematic-Isotropic Transition in MBBA and its Mixtures with 4-
Methoxybenzaldehyde: Applications to the Purity Control of Liquid Crystals. Mol. Cryst. Liq. Cryst. 1979,
51, 57–61, 10.1080/00268947908084692
102
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Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
Absorption Coefficient of Tricot Warp Knitting Fabrics as
Acoustic Textile Materials
Nuvalu Asidiq1 and Achmad Ibrahim Makki 2*
1 Politeknik STTT Bandung: Nuvalu Asidiq ; [email protected]
2 Politeknik STTT Bandung: Achmad Ibrahim Makki ; [email protected]
* Correspondence: [email protected]; Tel: +62-812-213-3040
Abstract : Acoustic textiles generally use materials from natural or artificial fibers made by nonwoven
or composite processes as sound absorption. The material has less aesthetic appearance, so it needs to
be layered again with woven or knitted fabrics. This study, using 3 types 4-layered tricot warp knit
fabrics with the characteristics related to thickness, density and porosity as the parameters for sound
absorption material, aims to achieve a predetermined absorption coefficient value and have good
aesthetics than nonwoven. The sound absorption test uses the impedance tube method at frequencies
of 63 Hz to 6000 Hz with Retrieving data at a standard frequency of 100 Hz and a high frequency of
6000 Hz. The result shows that the structure of tricot with the highest density is the best fabric for
sound absorption for it has the highest sound coefficient value.
Keywords: tricot knit fabric; acoustic textile; coefficient absorption
ISBN : 978-623-91916-0-3
1. Introduction
Sound pollution is caused by high-volume sounds that make the surrounding area noisy and
unpleasant. The effect of sound pollution on the environment can interfere verbal communication,
causing illness, stress, changes in blood pressure, and disorders of hearing such as temporary hearing
loss, or permanent damage to the sense of hearing.
Acoustic textiles come from two words namely "textiles" and "acoustics". Textile is a flexible
material made from woven yarn, knitting, and joining fibers. Acoustics is the study of sound, how
sound is produced, propagation, and learning how the medium responds to sound, and the
characteristics of sound. Acoustic textiles can be defined as flexible material from the process of
weaving, knitting, and joining fibers which are used as a medium to respond to the sounds. Acoustic
textiles are one part of the development of textiles namely technical textiles which have a special
function as sound absorption. Sound absorption is a fabric absorbent material that can reduce noise.
In research on acoustic textiles many nonwoven and composite materials were used as sound
absorption. The aesthetics of these materials are less good than woven and knit fabrics. Sound
absorption materials from nonwovens and composites can be layered with woven or knit fabrics to
add aesthetics.
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Noerati : Study on Cellulose Sponges Reinforced by Viscose Rayon Fibers
This research uses material from warp knit fabric (3D fabric) which has better thickness and
density than woven fabric as shown in Figure 1, and has a good aesthetic appearance. The thicker the
fabric, the more the sound waves from sources that propagate through the media will be absorbed by
the fabric (absorption). The thinner the fabric, the less sound waves that propagate through the media
will be absorbed. The thickness of the fabric affects the value of the sound absorption coefficient. At
low frequencies, in high fabric density, the sound waves will be reflected by the media (reflection)
and in lower fabric density, the sound waves from sources propagate only through the fabric media
(transmission). The fabric density greatly affects the coefficient of sound absorption at high
frequencies.
Figure 1. Difference in thickness of woven fabric and tricot warp knit fabric
2. Method
The acoustic testing method with the impedance tube method based on the ISO 10534-2 test
standard was carried out on three samples of the tricot warp knit fabric with code names 93201A,
93127C, and 93172B. Each structure has a different density and porosity with the same fabric
thickness of 2.4 mm. Knit fabric is made in warp knitting machine using 4 guide bars. The design of
the tricot warp knit fabric is made using the ProCad warpknit 5 program. The yarn used in making
the sample is polyester yarn.
Acoustic testing is carried out at low, medium and high frequencies with frequency ranges
according to ISO 11564. To support the analysis of the sample, the fabric thickness will be tested, and
the density and porosity will be calculated.
3. Results and Discussion
The fabric structure of the lapping diagram made can be seen in Figure 2. There is a difference in
the structure of the three fabrics produced. Lapping diagrams of each fabric can be seen in Figure 3.
Tricot warp fabric with four layers of fabric is used to obtain thickness and density of acoustic
material that exceeds normal acoustic material. Absorption coefficients of the three fabrics can be seen
in Table 1. Low, medium and high frequencies are given in tests with a minimum frequency of 100
Hz. and a maximum of 6000 Hz. Absorption coefficient graph at each frequency can be seen in Figure
4.
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Noerati : Study on Cellulose Sponges Reinforced by Viscose Rayon Fibers
(a) (b) (c)
Figure 2. Structure of the tricot warp knit fabric, (a): 93201A, (b): 93127C, and (c): 93172B
(a) (b)
(c)
Figure 3. Lapping Diagram of the tricot warp knit fabric, (a): 93201A, (b): 93127C, and (c): 93172B
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Noerati : Study on Cellulose Sponges Reinforced by Viscose Rayon Fibers
Sample number 93172B gives a relatively high sound absorption coefficient value of 0.72 α.
Tricot warp knit fabric 93127C provides sound absorption coefficient with a value of 0.49 α. As for the
tricot warp knit fabric 93201A structure has a relatively low value with a value of 0.30 α. Tricot warp
knit fabric 93172B has the highest absorption coefficient compared to other warp tricot knit fabric.
This is because the tricot warp knit fabric 93172B has high density and good porosity compared to
other fabrics.
Table 1. Test results on tricot warp knit fabrics
Figure 4. Relation of frequency to sound absorption coefficient
The results of the porosity and density calculations of each fabric are shown in table 2. The
relationship between fabric density and sound absorption coefficient, and fabric porosity and sound
absorption coefficient can be seen in Figure 5.
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Table 2. Density and Porosity on tricot warp knit fabrics
Type of Fabric Thickness Density Porosity
93201A 2.4 0.4505 0.3982
93127C 2.4 0.5227 0.3459
93172B 2.4 0.6379 0.2624
(a) (b)
Figure 5. The relationship of fabric density to sound absorption coefficient (a) and porosity
relationship to sound absorption coefficient (b)
Sound absorption coefficient values increase in fabric samples that have high density values. The
higher the fabric traffic value, the better the sound waves from the source propagating through the
media will be absorbed by the fabric. Moreover, the smaller the fabric density, the less the sound
waves propagating through the media will be absorbed (only partially). It means that the rest will be
transmitted so that the absorption value is smaller. Material density shows the mass concentration of
a material, which is measured as mass per unit volume. For materials with porous structures, material
density is important in acoustic absorption. When the density structure is high, the sound absorption
value will be high. High density materials are used to absorb high frequency noise. If the density
structure is small, the sound absorption produced is small. This is related to the fabric porosity.
In inverse proportion to density, the value of sound absorption coefficient increases in fabric
samples that have a small porosity value. The smaller the porosity value of the fabric, the more sound
waves from sources that touch the fabric surface will be reflected (reflection). However, the greater
the porosity of the fabric, the more sound waves that touch the fabric will be transmitted
(transmission) by the fabric. The porosity of a material indicates the amount of empty space or
emptiness in a structure. In the case of porous sound absorbers, the type, size and number of pores
affect sound absorption. The higher the number of pores in a large structure or porosity, usually the
smaller density of the mass of small porous material will be, which enable the sound absorption to be
large. Conversely, the lower the porosity of a small structure, the bigger the mass density will be, so
the sound absorption will be small because the sound through the fabric is mostly reflected back.
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4. Conclusion
Tricot warp knit fabric can be used as a sound absorbent. Thickness, density, and porosity affect
the sound absorption coefficient. The higher the density is, the higher the absorption coefficient will
be. Otherwise, the higher the porosity is, the lower the absorption coefficient will be. A combination
of nonwoven or composite with a tricot knit fabric can be proposed to become an alternative sound
absorbent that has a function as a good sound absorber and also a good aesthetic function.
References
1. Adella Kusmala Dewi dan Elvaswer, 2015. Material Akustik Serat Pelepah Pisang (Musa acuminax
balbasiana calla) Sebagai Pengendali Polusi Bunyi. Jurnal Fisika Unand Vol. 4, No. 1, Januari 2015 ISSN
2302-8491.
2. A Richard Horrocks, Subhash C. Anand, 2016. Handbook of Technical Textiles. United Kingdom: Woodhead
Publishing.
3. Buku Teknologi Perajutan I, Sekolah Tinggi Teknologi Tekstil.
4. David J. Spencer, 1983. Knitting Teknology. United Kingdom: Woodhead Publishing.
5. David J. Spencer, 2001. Knitting Teknology Third Edition. United Kingdom: Woodhead Publishing.
6. Doelle, L Leslie, 1985. Akustik Lingkungan. Terjemahan Oleh Lea Prasetia: Surabaya: Erlangga
7. Hasina Mamtaz dkk, 2016. Acoustic Absorption of Natural Fiber Composites.
8. ISO 10534-2:1998, Acoustics -- Determination of Sound Absorption Coefficient in Impedance Tubes –
Transfer Method.
9. ISO 11654:1997, Acoustics -- Sound Absorbers for Use in Buildings -- Rating of Sound Absorption.
10. ISO 354:2003, Acoustics -- Measurement of Sound Absorption in a Reverberation Room.
11. Mediastika, C. 2009. Akustik Bangunan. Erlangga: Jakarta.
12. Parham Soltani & Mohammad Zarrebini, 2013. Acoustic Performance of Woven Fabrics in Relation to
Structural Parameters and Air Permeability. Journal of The Textile Institute, Number: 1072954.
13. Prasasto Satwiko, 2009. Fisika Bangunan. Andi: Yogyakarta.
14. Rajiv Padhye & Rajkishore Nayak, 2016. Acoustic Textiles.
15. Sasongko dkk, 2000. Kebisingan Lingkungan. Badan penerbit UNDIP Semarang.
16. Shishoo R, 2009. Textile advances in the automotive industry. Woodhead Publishing Limited, Cambridge.
17. SNI 08-0458-1989, Kain Rajut Pakan, Cara Uji Konstruksi, Badan Standardisasi Nasional.
18. Soeprijono dkk, 1973. Serat-serat Tekstil
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Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
The Effect of Tetraethoxysilane as Filler on
UHMWPE (Ultrahigh Molecular Weight
Polyethylene)/HDPE Composites
Febrianti Nurul Hidayah, S.T., B.Sc., M.Sc.1
1Textile Engineering Department, Faculty of Industrial Technology, Universitas Islam
Indonesia,Yogyakarta
* Correspondence : [email protected]; Tel.: (+62895363326156)
Abstract : The needed of high performance fibres in technical textile industry is higher from time-
to-time since it can replace the heavy metal properties demand. One of popular fibres beside
aramid and carbon is called ultrahigh molecular weight polyethylene (UHMWPE) which the high
performance polyethylene in numerous research have been observing. Based on some studies,
UHMWPE has low adhesion to polymer matrix. Therefore, in this research, to improve the
adhesion between UHMWPE fibre and polymer matrix, tetraexthoxysilane was filled into
UHMWPE/HDPE surface. The interlaminar shear strength (ILSS) and mechanical properties of the
composite were investigated, in comparison with those of the composite without any fillers. In
addition, the surface morphology and structure of UHMWPE/HDPE composite filled with TEOS
were studied by SEM and EDS. The results showed the ILSS with TEOS improved only 15% from
those without fillers but the shear modulus was twice higher. By SEM observation, it showed that
UHMWPE/HDPE composite surface was observed with some particles attached. Although there
was no chemical interaction between TEOS and UHMWPE/HDPE chains, TEOS has some
interaction with UHMWPE molecular chains according to the results of EDS. The TEOS coatings
have an effect on the adhesion may be associated with the roughened surface of the composite and
upon intermolecular interaction.
Keywords : UHMWPE, HDPE, TEOS, composite, filler, Interlaminar shear
ISBN : 978-623-91916-0-3
1. Introduction
UHMWPE is a linear polyethylene with a molecular weight usually between 3.1 and 5.67 million,
and has an average molecular weight more than 2*106 g mol-1 [1,2]. Since they have outstanding
toughness and chemical resistance, UHMWPE fibres are used in a diverse applications including
personal armor, cut-resistant gloves, high-performance sails, artificial joints, and moving parts on
weaving machines [3]. In addition, the fibre currently competes with aramid in bulletproof vests,
therefore interlaminar shear strength is significantly important as one of main mechanical properties.
UHMWPE fibres have weakness point in wear-resistance and anti-creep properties, therefore,
attempts have been conducted by researchers to improve them by filling with in-organic filler,
cement, fibre, etc [4-6]. The other approach used is by chemical crosslinking that is introduced by
Lewis [7] yet the specific crosslinking using silane was developed since 1970s in insulation materials
of high voltage electric cables [8]. Another study by Atkinson and Cicek [9] was also conducted where
the silane crosslinked polyethylene for orthopedic applications. However, only slight information is
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Febrianti Nurul Hidayah: The Effect of Tetraethoxysilane as Filler on UHMWPE (Ultrahigh Molecular Weight Polyethylene)/HDPE
Composites
available on silane crosslinked UHMWPE, which one of them is the study of Sung In Moon [10], that
applied organo alkoxysilane ( -methylmethacryloxypropyltrimethoxysilane) where it could improve
ILSS of UHMWPE from 8 to 16 MPa. Therefore, in this study, UHMWPE was tried to be crosslinked
by other silane called tetraethoxysilane with the aim of improving its mechanical and interlaminar
shear properties.
2. Materials and Methods
To make a plate of composite, reinforcement and matrix/resin should be needed. In this study,
main reinforce used was UHMWPE tapes (Endumax®) which obtained from Teijin B.V. (The
Netherlands), and the matrix was HDPE. The calendaring and curing process for HDPE was set at
130ºC 50 bar for 10 minutes. Each sheet was stacked until the thickness of approximately 4-5 mm,
then pressed/cured in the press. Variables for each treatment were differentiated by temperature,
pressure and time. Practical approach was applied by using a filler called TEOS which was set on 88%
weight of previous calendared UHMWPE/HDPE sheets by immersing the sheets in TEOS in vacuum
desiccator for total of 70 hours and drying the sheets at 80ºC for 24 hours. The curing process was set
on 50 bar at 130 ºC for 10 minutes. Each composite plates then prepared for tests by cutting them in
different dimension as requirement of the test with use of Eurolaser® cutter machine.
The standard reference used for ILSS test was ASTM D2344-48 (Test methods for Apparent
Interlaminar Shear Strength of Parallel Fiber Composites by Short-Beam Method). ILSS test was
applied by 3-point-bending test method with Instron® load cell of 1kN, 5 kN and 10 kN (span-to-
depth ratio was 4:1 and the loading speed was 2 mm/min). The thickness of sample was
approximately 5 mm and the width was 9 mm [11]. On the other hand, this study also refers to ASTM
D790 (Test methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical
Insulating Materials). The bending properties test was applied by 3-point-bending test as well with
loading speed of 2 mm/min. The thickness of sample was approximately 5 mm and width of 13 mm.
[12].
3. Results
As aimed in this research, to improve the adhesion between UHMWPE fibre and polymer
matrix, tetraexthoxysilane was filled into UHMWPE/HDPE surface. The mechanical properties of the
composite were investigated, in comparison with those of the composite without any fillers. The
mechanical properties included interlaminar shear strength, shear modulus, bending strength and
bending modulus are shown below.
Table 1. Mechanical test results of ILSS test on UHMWPE based composites
Mechanical Properties UHMWPE/HDPE UHMWPE/HDPE+TEOS
ILSS (MPa) 5.17 ± 0.04 5.98 ± 0.06
Shear Modulus (MPa) 99 ± 3 184 ± 7
Bending Strength (MPa) 78 ± 1 55 ± 5
Bending Modulus (GPa) 19.7 ± 0.6 41 ± 1
Density (g/cm3) 0.94 0.94
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Composites
4. DiscussionStress (MPa)
The chosen filler applied in this research was TEOS that aimed to get silica layer into the
composite and expected to higher the mechanical properties. The concentration of TEOS was 88% of
UHMWPE/HDPE sheets in total weight. This concentration was chosen because TEOS (liquid form)
should get into all pores inside the UHMWPE sheets in immersing box (sheets thickness was about 4
mm). Therefore, the setting also took the advantage of vacuum and desiccator to allow silane getting
into the pores of UHMWPE. The curing processes of both composite samples (with and without
TEOS) were same, 50 bar for 10 minutes at 130ºC. There was no other heating process after the curing,
but the cooling process took place at room temperature inside the laboratory cabinet to stabilize both
composites before mechanical tests.
The mechanical properties of two composites before and after adding filler (TEOS) for 24 hours
are presented in Table 1. It can be seen that the result on Table 1 shows that TEOS gave partial
positive influence on ILSS by increasing its value with the same pressure, temperature and time
condition; from 5.17 MPa to 5.98 MPa that approximately 15% higher. Meanwhile, the shear modulus
and bending modulus were twice higher from 99 MPa to 184 MPa and 19.7 to 41 GPa, respectively.
This means that the treatments by adding filler have an no significant effect on ILSS but play a role in
increasing the bending modulus of the composites.
Besides the mechanical properties shown on Table 1, the stress-strain curve was also given below
in Figure 1. The curve indicates whether the composites are ductile or brittle. The blue line represents
UHMWPE/HDPE composite that shows the material has lower stress but higher strain which also
means it is ductile and has characteristic of plastic but large toughness since it absorbs more energy
under the curve.
50
40
30
20
UHMWPE/HDPE
10
UHMWPE/HDPE+TEOS
0
0,00 1,50 3,00 4,50 6,01 7,51 9,01 10,52 12,02
Strain (%)
Figure 1. Stress-strain curve of UHMWPE/HDPE composites with and without TEOS shows the
elasticity of the composites where the blue line represents UHMWPE/HDPE composite (more
ductile) while the grey line represents UHMWPE/HDPE/TEOS composite (more brittle)
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Composites
On the other hand, the grey line represents UHMWPE/HDPE composites which treated with
TEOS showing a higher peak and stress but lower strain. This means the adding of TEOS significantly
gives impact to the composite in term of elasticity. By adding TEOS, the composites become brittle
and has smaller toughness because it absorbs less energy under the curve. Moreover, the relation
between Table 1 and Figure 1 can explain that number of bending and shear modulus (Table 1) are
twice higher indicates the increase of stiffness (brittle) and strength of the material which presents
with higher peak of UHMWPE/HDPE/TEOS in stress-strain curve.
Moreover, there are some representative pictures in microscope scale revealed what happened in
the bar of UHMWPE/HDPE composite. This scanning electron microscope analysis was done to
determine the failure mechanism which indicates shear behavior as well.
Adhesive Cohesive delamination
delamination
Cohesive
delamination
Endumax®
Endumax®
HDPE foil
Endumax®
(a) (b)
Figure 2. (a) UHMWPE/HDPE appearance on SEM with scale of 10 µm and magnification of
500times shows two types of delamination and (b) scale of 100µm 100 times magnification : the
delamination first happened in the interphase of UHMWPE/HDPE then soon followed by
delamination within UHMWPE itself
Based on Figure 2 above, there are two types of delamination/failure on UHMWPE/HDPE
composite. The first delamination is called cohesive delamination where the delamination happens
between two different materials: UHMWPE and HDPE. The second delamination is called adhesive
delamination where this failure occurs within one material, in this case is UHMWPE tape. The only
delamination that did not occur in this phase is HDPE itself. Thus it could be also concluded that
UHMWPE has low adhesion towards HDPE. The conclusion could be first delamination started on
HDPE-UHMWPE interphase then soon after that cracked inside the UHMWPE.
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Composites
Silica
Endumax® HDPE
layers
Figure 3. Silica was shown as cracked part on spot between HDPE and Endumax (scale 10µm
magnification of 500 times)
Figure 4. Silica was found in some spots in the interphase. It was shown by SEM (left) and while
the right figure is by EDS mapping to read signal of Si (Silica) from the same spots.
Figure 5. EDS mapping of the components from Figure 4 where the Si (Silica) element
concentration was present. The other components (C,O) were part of the polyethylene composite
while Pt and Pd was used as coating for microscope purpose
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Composites
On the other words, Silica was barely hard to find from layers in between UHMWPE/HDPE on
SEM analysis (Figure 3). The silica was found cracked and it was on low silica concentration by
observing on EDS mapping in the same spot as it found (Figure 4 and 5). As obtained from previous
SEM of only UHMWPE/HDPE, here delamination also occurred on interphase of UHMWPE/HDPE
and within UHMWPE (cohesive and adhesive delamination). The silica kept outside the layer instead
of getting into pores. On EDS mapping on figure 5 presents the percentage of silica was low which
indicates TEOS was not absorbed enough into the layers of UHMWPE/HDPE composite.
5. Conclusion
In order to improve the interlaminar shear strength of UHMWPE fiber-reinforced polymer
matrix composites, specifically UHMWPE/HDPE composite, filler was added to the system, named
tetraethoxysilane (TEOS) which has been observed. According to the above analysis, the difference
between UHMWPE/HDPE composite with UHMWPE/HDPE filled TEOS was not significant in term
of interlaminar shear behaviour. The silica layer on UHMWPE/HDPE may increase the interfacial
adhesion of UHMWPE/HDPE composites whose interface did not posses a chemical binding, but the
higher ILSS could be achieved even only 15%. This means the interlaminar between UHMPWE fibres
and HDPE in composite system obtained higher strength physically not chemically since the TEOS
could not be filled into the pores of the fibre. In term of elasticity, by adding TEOS, the
UHMWPE/HDPE composites became more brittle and absorbed more energy under the curve of
stress-strain. The significant higher value of ILSS was not obtained, however, we knew the failure
mechanism by experiments: the weak part of UHMWPE was in UHMWPE tape fibrils inside the
composite, even adding the filler (TEOS) did not improve the fibrils properties. Therefore, for further
experiment, the focus should not only be targetted on surface treatment, but also more onto the fibrils
level area such as x-ray treatment or practical approach in molecular area. Then this result will be
expected to higher the strength of UHMWPE based composite which later could be applied in future
technical textile production.
References
1. Tang, CY., Xie, XL., Wu, XC., Li, RKY., Ma,YW. Enhanced wear performance of UHMWPE
crosslinked by organosilane, Journal of Materials.Science , 2002, 13, pp. 1065-1069
2. Stein, H. L. Ultrahigh molecular weight polyethylenes (UHMWPE). In Engineered Materials
Handbook, 1998, 2, pp. 167–171.
3. Bhatnagar, A. (ed.) Lightweight Ballistic Composites: Military and Law-Enforcement
Applications. Honeywell International, 2006, ISBN 1855739410
4. Suwanprateeb, J. Binary and ternary particulated composites : UHMWPE/CaCO3/HDPE.
Journal of Applied Polymer Science, 2000, 75, pp. 1503.
5. Liu, CZ., Ren, LQ., Tong, J., Joyce, T.J., Green, S.M. and Arnell, R.D. Statistical Wear analysis of
PA-6/UHMWPE alloy, UHMWPE and PA-6. Wear, 2001, 249, pp. 31-36.
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Composites
6. Que, L. and Topoleski, LDT. Third-body wear of cobalt-chromium-molybdenum implant
alloys initiated by bone and poly (methyl methacrylate) particles. Polymer Engineering Science,
2000, 50, pp. 322.
7. Lewis, G. Properties of crosslinked ultra-high-molecular-weight-polyethylene. Biomaterials,
2001, 22, pp. 371.
8. Peacock, A.J. ( “Handbook of Polyethylene: Structures, Properties and Applications”. Marcel
Dekker Inc : New York, 2000.
9. Atkinson, J.R. and Cicek, R.Z. Biomaterials, 1985, 24, pp. 267.
10. Sung In Moon, J. J.. The role of additional silane coupling agent treatment in oxygen plasma-
treated UHMWPE fiber/vinylester composites. Journal Adhesion Scientific Technology, 2000, 14,
pp. 493-506.
11. ASTM International. ASTM D2344-84. Standard Test Method for Apparent Interlaminar Shear
Strength of Parallel Fiber Composites by Short-Beam Methods. PA, USA: ASTM Committee on
Standards,1995.
12. ASTM International. ASTM D790-02. Standard Test Methods for Flexural Properties of
Unreinforced and Reinforced Plastic and Electrical Insulating Materials. PA, USA: ASTM
Committee on Standards, 2002.
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Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
Preliminary Study of Preparation and
Characterizations of Carbon-Based
Materials-Embedded on Nanocomposites Fiber for
Smart Textile Applications
Andri Hardiansyah1, Yuyun lrmawati1, Fredina Destyorini1, Henry Widodo1, Nanik
Indayaningsih1, Deni Shidqi Khaerudini1, Rike Yudianti1*
1Research Center for Physics, Indonesian Institutes of Sciences, Komplek Puspiptek Tangerang Selatan, Banten,
Indonesia 15314
*Correspondence: [email protected]
Abstract: Carbon-based materials-embedded on nanocomposites fiber are interesting due their unique
properties for versatile application such as smart textile or electro or e-textile. Herein, functionalized
multi-walled carbon nanotube (MWCNT)/polyvinyl alcohol (PVA) and graphene oxide (GO)/PVA
nanocomposites fibers were developed through rotational wet spinning process. The resultant of
nanocomposites fiber was characterized systematically through optical microscopy (OM), scanning
electron microscopy (SEM), resistivity test, tensile test, and sensitivity test. Based on SEM observation,
the diameter of pristine MWCNT/PVA and GO/PVA nanocomposites fibers were around 260 and 200
μm, respectively. The results show that MWCNT/PVA nanocomposites fibers with the ratio of 1:5
show higher tensile strength and elongation in compare with GO/PVA nanocomposites fibers with the
ratio of 1:5. According to the resistivity test, MWCNT/PVA nanocomposites fiber shows the
conductivity values in the range of 10-2 S/cm. Dispersion and arrangement of carbon-based materials
on the polymer matrix are supposed to be the main factor that influenced nanocomposites fiber
properties including the mechanical and electrical properties. Therefore, these nanocomposites fiber
are anticipated to be developed as a component for smart fabric or smart textiles.
Keywords: Wet spinning; nanocomposites; smart textiles; carbon-based material
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1. Introduction
Nanocomposites fiber exhibits interesting features and properties that could be developed for
versatile applications such as smart fabric and smart textiles. Nanocomposites fiber can be developed
through incorporation of inorganic materials as fillers on the organic materials (polymer) as a matrix.
The combination of these two different materials is designed to take the advantages from their
materials properties. As a matrix, polymeric materials provide a flexible and elastic feature,
meanwhile as a filler, inorganic materials can be used as a support for mechanical or electrical
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Hardiansyah, Preliminary Study of Preparation and characterizations of carbon-based
characteristics. Various carbon-based materials including carbon nanotube (CNT) [1] or
graphene-based materials have been developed as a filler in polymeric system [2]. Previous research
conducted by Min Kyoon Shin et al has developed reduced graphene oxide flakes and CNT
incorporated in PVA matrix system [3]. Pei Zhang et al prepared MWCNT grafted PVA through
alkylation [4].
Wet spinning is an efficient method to develop nanocomposites fiber material [5]. Fibers that
are developed from wet spinning process are anticipated to be used for wearable strain sensors [5].
Herein, PVA was used as matrix and carbon-based material (MWCNT or GO) as filler for polymer
nanocomposites. PVA is one of hydrophilic polymer that is commonly developed as spun-fiber [6, 7].
Surfactant plays an important role in order to improve the dispersion and interfacial bonding between
CNT and polymeric materials which generate the stable colloidal system [8, 9].
In this study, nanocomposites fiber based on PVA and MWCNT or GO as a matrix and filler,
respectively, were developed through rotational wet spinning process. The resultant of
nanocomposites fiber was evaluated mainly in term of structure, morphology, and electrical properties
through OM, SEM, and resistivity measurement, respectively. Their potential application for smart
fabric or smart textile would be evaluated.
2. Materials and Methods
2.1 Materials
PVA and sodium dodecyl sulphate (SDS, C12H25SO4Na) were purchased from Sigma Aldrich.
Acetone was purchased from Merck. MWCNT was purchased from Chengdu China. Furthermore,
MWCNT was functionalized via acid treatment. Aqua demineralization was used throughout
experiments. All chemical were used as received without any further purification.
2.2 Preparation of MWCNT/PVA and GO/PVA nanocomposites fibers
Briefly, water was chosen as dispersing medium for MWCNT or GO through probe sonication
and as solvent for PVA. SDS was used as surfactant-aided carbon-based dispersion in order to enhance
the MWCNT dispersion on the water system. The spinning dope composed of carbon-based
dispersion such us MWCNT or GO dispersed in PVA solution was loaded into 1 mL disposable
syringe installed in a syringe pump, which was continuously injected into acetone coagulation bath.
After injection, nanocomposites-based fiber were immersed in water for 30, 60, 90, and 120 minutes at
50oC and drying overnight on the vacuum condition at 50oC prior to characterization. These process
are expected to remove any residual surfactant [10]. In this study, the characteristics of resultant
nanocomposites fiber was also evaluated through immersion in water at room temperature for 24 h
and 48 h and commercially available detergent solution for 30 min at room temperature and 50οC.
Eventually, after washed with water and drying, the resistance values of the nanocomposite fiber were
measured. GO/PVA (1:5) nanocomposites fibers was prepared as the aforementioned process. The
resultant of GO/PVA nanocomposites fibers was evaluated in water immersion at room temperature
for 2h and 4h and water immersion at 50oC for 30, 60 and 90 min.
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Pump System
Syringe
Fiber
Coagulation Bath
Rotation
Figure 1. Schematic image and the set-up of the rotational wet spinning machine used to produce
the MWCNT/PVA or GO/PVA nanocomposites fiber
2.3 Characterizations
Structure and morphology of nanocomposites fiber were evaluated through SEM and OM
observation. Single filament tensile test (DMA Q 800 V20.26) was used to evaluate the mechanical
properties of the nanocomposites fiber. Resistivity of the resultant nanocomposites fiber was
measured by using digital multimeter. Preliminary studies of humidity sensing was evaluated
through humidity bottles containing metal salts saturated solutions of sodium chloride (NaCl) sealed
in glass bottles at 20 °C to obtain relative humidity (RH) conditions of 75%. The resistivity of
nanocomposites fiber during the sensitivity test was measured using a probe DC method with a
Keithley 2000 multimeter.
3. Results
3.1 Macroscopic observation of nanocomposites fiber
(a) (b) (c)
Figure 2. Production of nanocomposites fiber (a), as-spun fibers (b), schematics representation of a
weight (25 gram) was lifted using MWCNT/PVA (1:5) nanocomposites fiber
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3.2 SEM observation of pristine MWCNT/PVA (1:5) and (b) GO/PVA (1:5)
(a) (b) (c) (d)
(e) (f) (g) (h)
Figure 3. SEM and cross section SEM images of MWCNT/PVA (ratio of 1:5) (a-d) and GO/PVA (ratio
of 1:5) (e-h) nanocomposites fiber
3.3 Single filament tensile test measurement of pristine MWCNT/PVA (1:5) and (b) GO/PVA (1:5)
Stress (MPa)(a) 18 (b) 8 Stress (MPa)
16
14 7
12
10 6
8
6 5
4
2 4
0
0 2 4 6 8 10 3
Strain (%)
2
1
0
0123456
Strain (%)
Figure 4. Stress-strain curve of (a) MWCNT/PVA (1:5) and (b) GO/PVA (1:5) nanocomposites fiber
filament
3.4 Optical microscopy, nanocomposites fiber diameter measurement and conductivity
measurement
(e) 0.09 0.020
0.08
0.07 0.018
0.06
0.05Conductivity (S/cm) 0.016 Average Diameter (cm)
0.04
(a) (b) 0.03 0.014
(c) (d) 0.02
0.01 0.012
0.00
0.010
0.008
30 60 90 120
Immersion time at 50oC (minutes)
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Hardiansyah, Preliminary Study of Preparation and characterizations of carbon-basedAverage diameter (cm)
Figure 5. Optical images of MWCNT/PVA (1:5) nanocomposites fiber with immersion 50oC with the
immersion time of 30 (a), 60 (b), 90 (c), and 120 (d) min, and their average diameter and conductivity
values (e)
(e) 0.030
(a) (b) 0.015
0.000
(c) (d) Troom,24 h Troom,48 h Troom,30 min T 50oC,30 min
Detergent Detergent
Treatment
Figure 6. Optical images of MWCNT/PVA (1:5) nanocomposites fiber with immersion at room
temperature for 24 h (a) and 48 h (b) and with addition of commercial detergent at room temperature
(c) and at 50oC (d) and their average diameter (e)
(f) 0.024
(a) (b) (c) Average diameter (cm)
0.012
(d) (e) 0.000 T 50oC,
Troom,2 h Troom,4 h T 50oC, T 50oC, 90 min
30 min 60 min
Treatment
Figure 7. Optical images of GO/PVA (1:5) nanocomposites fiber with immersion at room temperature
for 2 h (a) and 4 h (b) and at 50oC with immersion time of 30 (c), 60 (d), and 90 (e) minutes and their
average diameters (f)
6 30 min
5
Resistivity (MOhm) 4
3
90 min
2 120 min
1 40 50 60 70 80
30 Relative Humidity (%)
Figure 8. Resistivity of MWCNT/PVA (1:5) nanocomposites fiber as a function of immersion time
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4. Discussion
4.1 Wet Spinning of MWCNT/PVA and GO/PVA Nanocomposites Fibers
Herein, wet spinning process was used to develop bulk nanocomposites fiber containing
polymeric material and carbon-based material as matrix and filler, respectively. Morphology
transformation was generated during the coagulation process in which spinning dope solution was
transformed into bulk MWCNT/PVA or GO/PVA nanocomposites fiber on acetone coagulation bath.
Immersion of nanocomposites fibers in water was conducted in order to remove any un-reacted
surfactant and impurities, followed by drying at room temperature. Their influence to fiber
morphology and electrical properties were investigated through OM observation and resistivity
measurement, respectively. The result shows that the morphology and electrical properties of
nanocomposites fiber were influenced by the immersion or washing process of nanocomposites fiber
in water system and drying process. Furthermore, SEM observation were conducted to evaluate the
structure and morphology of pristine nanocomposites fiber. Figure 3 shows selected SEM images of
MWCNT/PVA (1:5) and GO/PVA (1:5) nanocomposites fiber. According to the SEM observation, the
diameter of MWCNT/PVA (Figure 3a) was slightly larger than GO/PVA (Figure 3e) nanocomposites
fiber. The nanocomposites fiber surface was contoured due to the effect functionalized MWCNT
(Figure 3b) or GO sheets (Figure 3f) on the nanocomposites fiber. Cross section SEM images revealed
the connection between filler MWCNT (Figure 3c) or GO (Figure 3g) on the PVA matrix. The
connection of MWCNT and GO on the nanocomposites fiber appears tube-like ((Figure 3d) and
sheets-like connection (Figure 3h), respectively. Moreover, the arrangement of MWCNT and GO on
the nanocomposites fiber will affect the conductivity and mechanical properties of the nanocomposites
fiber.
4.2 Mechanical Properties
Single filament tensile test (DMA Q 800 V20.26) was conducted to evaluate the mechanical
properties of the nanocomposites fiber. Typical strain-stress curve of nanocomposites MWCNT/PVA
(1:5) and GO/PVA (1:5) nanocomposites fiber are shown in Figure 4. The maximum strain-to-failure
for MWCNT/PVA (1:5) and GO/PVA (1:5) nanocomposites fiber was about 10% and 5.5%,
respectively. The yield strength of MWCNT/PVA (1:5) and GO/PVA (1:5) nanocomposites fiber was
around 11 and 4.5 MPa, respectively. Based on the single filament tensile test, MWCNT/PVA (1:5)
exhibits higher tensile strength and elongation in compare with the GO/PVA (1:5). This might be due
to the characteristics of MWCNT that strengthen the nanocomposites fiber along with the tensile
direction. Moreover, the dispersion homogeneity of MWCNT on the PVA matrix plays an important
role in term of efficient stress-transfer between MWCNT as a filler and PVA as a matrix [11].
4.3 Morphology and Electrical Properties of MWCNT/PVA and GO/PVA Nanocomposites Fibers
Figure 5 shows the OM images of the MWCNT/PVA (1:5) nanocomposites fiber with variation of
immersion process at 50oC for 30, 60, 90, and 120 minutes. After immersion the fiber was dried to
remove any water. Nanocomposites fiber spun with MWCNT loading exhibits electrical conductivity
properties. Figure 5 shows the average diameter and conductivity value of MWCNT/PVA (1:5)
nanocomposites fiber against immersion time in water at 50ᵒC. Increasing the immersion time to 120
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minutes will enhance the conductivity value of MWCNT/PVA (1:5) nanocomposites fiber and decrease
the average diameter of nanocomposites fiber. This might happen because during the immersion time
the unreacted surfactant will be removed [6], thus decrease the average diameter of nanocomposites
fiber and lower the resistivity barrier between MWCNT which then enhance the conductivity value of
nanocomposites fiber.
In this study, immersion of MWCNT/PVA (1:5) was also conducted at various parameter such
as water immersion at room temperature for 24 h and 48 h and also immersion at commercial
detergent at room temperature and at 50oC (Figure 6) with the average diameter results of 0.0148,
0.0141, 0.0151 and 0.0143 cm respectively. Moreover, this MWCNT/PVA (1:5) nanocomposites fiber
still maintains the fiber after being washed in water and drying. Therefore, it is anticipated that the
nanocomposites fiber can be developed as washable fiber or textiles.
On the other side, with the same process as the aforementioned method, the diameter of
GO/PVA nanocomposites diameter was 0.0117, 0.0103, 0.0124, 0.0122, and 0.0124 cm for immersion at
room temperature for 2h and 4 h and immersion at 50oC for 30, 60, and 90 minutes, respectively
(Figure 7).
4.4 Sensing Characteristic
Herein, preliminary research about sensing characteristics of the selected nanocomposites
fiber was conducted for MWCNT/PVA (1:5) nanocomposites fiber with immersion time of 30, 90, and
120 minute. Figure 8 shows the relative humidity against resistivity value of MWCNT/PVA (1:5)
nanocomposites fiber. Increasing immersion time decrease the measured resistivity. The measured
resistivity at the relative humidity of 74% (for saturated sodium chloride at 20oC) was 5.93 ± 0.17, 2.27 ±
0.27 and 1.68 ± 0.62 M ohm for the nanocomposites fiber with immersion time of 30, 90, and 120
minutes, respectively. These characteristics was in accordance with the conductivity test in which the
MWCNT/PVA (1:5) nanocomposites fiber with the immersion time of 120 minutes presents in the
highest conductivity.
5. Conclusions
We have developed nanocomposites fiber based on the polymeric material PVA with the
incorporation of carbon-based material including MWCNT or GO. The conductivity value of
MWCNT/PVA was about 10-2 S/cm, and increasing the immersion time enhance the conductivity. The
presence of conductive properties can be developed for the e-textile or textile-based sensing. After
washing with commercial detergent, the nanocomposites fiber still maintains its morphology which
represented their washability. According to the results, this nanocomposites fiber are anticipated to be
developed for smart textiles or smart fabric.
Acknowledgments: This work is supported by the Korea Institute of Materials Sciences (KIMS). Facilities were
supported by Dr. Joon-Hyung Byun is gratefully acknowledged. We are also grateful to the Dr. Zuoli He for help
with SEM and single filament tensile test.
Author Contributions: AH and RY are the main contributor for this manuscript. AH and RY conceived and
designed the experiments; AH, RY, and YI performed the experiments; AH, RY, and YI analyzed the data; RY,
YY, FD, HW, NI and DSK contributed reagents/materials/analysis tools; AH and RY wrote the paper.
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Conflicts of Interest: The authors declare no conflict of interest
References
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self-alignment of reduced graphene oxide and carbon nanotubes. Nature Communications 2012;3:650.
4. Zhang P, Qiu D, Chen H, Sun J, Wang J, Qin C, et al. Preparation of MWCNTs grafted with polyvinyl alcohol
through Friedel–Crafts alkylation and their composite fibers with enhanced mechanical properties. Journal
of Materials Chemistry A 2015;3:1442-9.
5. Tang Z, Jia S, Wang F, Bian C, Chen Y, Wang Y, et al. Highly Stretchable Core–Sheath Fibers via
Wet-Spinning for Wearable Strain Sensors. ACS Applied Materials & Interfaces 2018;10:6624-35.
6. Mercader C, Denis-Lutard V, Jestin S, Maugey M, Derré A, Zakri C, et al. Scalable process for the spinning of
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7. Lai D, Yizhe W, Zou L, Xu Y, Lu H. Wet spinning of PVA composite fibers with a large fraction of
multi-walled carbon nanotubes2015.
8] Gong X, Liu J, Baskaran S, Voise RD, Young JS. Surfactant-Assisted Processing of Carbon Nanotube/Polymer
Composites. Chemistry of Materials 2000;12:1049-52.
[9. Grossiord N, Loos J, Regev O, Koning CE. Toolbox for Dispersing Carbon Nanotubes into Polymers To Get
Conductive Nanocomposites. Chemistry of Materials 2006;18:1089-99.
10. Wu X, Morimoto T, Mukai K, Asaka K, Okazaki T. Relationship between Mechanical and Electrical
Properties of Continuous Polymer-Free Carbon Nanotube Fibers by Wet-Spinning Method and
Nanotube-Length Estimated by Far-Infrared Spectroscopy. The Journal of Physical Chemistry C
2016;120:20419-27.
11. Lai D, Wei Y, Zou L, Xu Y, Lu H. Wet spinning of PVA composite fibers with a large fraction of multi-walled
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ISBN : 978-623-91916-0-3 123
DOI : 10.5281/zenodo.3470923
Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
The Making of Geotextiles from Raw Waste of Wool
Merino and Plastic using the Thermal Bonding
Method
Agung Setia Budi 1, Asril Senoaji Soekoco 2
1 [email protected], Politeknik STTT Bandung
2 [email protected], Politeknik STTT Bandung
* Correspondence: [email protected]; Tel.: -
Abstract : Merino Sheep is a type of sheep that can produce two main products in the form of meat
and fleece (wool). Lamb fur is still considered by breeders as stool-like waste, so its utilization is still
lacking. in recent years there have been innovations in wool products to be applied to technical needs
such as nonwoven fabric used for thermal and acoustic insulating materials in construction and the
automotive or geotextile industries. This geotextile for wool fiber is made using the thermal bonding
method, where wool fibers are mixed with thermoplastic fibers. To minimize the using of energy, the
adhesive used is plastic polyethylene waste with a content variation 50%, 45%, and 40% of plastics
and aims to get weight per meter square, moisture content and moisture regain, tensile strength, and
bursting strength from the fabric. The test results obtained have been compared with the standard.
The nonwoven fabric from a raw waste of wool merino and plastic can be made with the thermal
bonding method and can be used geotextiles for erosion control, but not for construction scale.
Keywords : wool; geotextiles; thermal bonding
ISBN : 978-623-91916-0-3
1. Introduction
Sheep livestock is one of the most developed farms in Indonesia. Many sheep are kept in rural
and suburban areas. In Figure 1 below is the population according to the Directorate General of
Livestock and Health Data until August 2018.
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Description: *) Temporary numbers
Source: Directorate General of Livestock and Health
Figure 1. Sheep population in Indonesia
Sheep are generally kept for meat production purposes and a small portion is for savings or for
hobbies such as fighting art. There are so many types that exist in sheep populations in Indonesia,
including Garut Sheep, Priangan Sheep, Fat Tail Sheep, Merino Breeds Sheep, and Merino Sheep. Can
be seen in Figure 1.1, the number of sheep populations in Indonesia in 2018 was 17,397,696, of which
13.77% were spread in Central Java Province.
One area that has sheep is in the Wonosobo Regency area. According to the Central Java
Province Animal Husbandry and Animal Health Service data until September 24, 2018, the
population of sheep in Wonosobo reaches 105,534. Where one type of sheep in cattle is the Merino
Sheep. Merino sheep is a type of dual-function sheep, namely sheep which can produce two main
products in the form of meat and fleece (wool) (Huda, Nasich, & Nuryadi, 2015).
Wool is still considered by breeders as stool-like waste, so its utilization is still lacking. The use
of wool has not been done much because of the limited knowledge of farmers. The breeders tend to
throw away their wool after shaving the sheep so that the wool becomes waste on the ground or
burned. Incorrect wool disposal creates ecological problems and contributes significantly to soil and
air pollution (Roman Niznikowski, 2006).
Wool is produced by shearing fleece activities that are carried out 1-2 times a year for females
while males are carried out every 2-4 months. Where each local sheep is able to produce 1 kg of
wool/tail in a single shear, so that the potential of sheep hair which is considered to be waste can be
utilized at 105,534 kg in one shave which if used as a product, will produce high economic value so
that farmers can increase their income.
Wool is a natural fiber so that the fiber can decompose naturally in the soil in a matter of years,
and will slowly release valuable nutrients back to earth. Wool has anti-tangle properties, can absorb
large amounts of water vapor, can store temperature, is fire resistant and resistant to UV light
(Jumaeri, 1977). 125
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Agung: The Making of Geotextiles from Raw Waste of Wool Merino and Plastic Using the Thermal Bonding Method
So far, fleece has been used for the production of carpets and other interior textiles. In the last
few years, there have been innovations in some products from fleece which have not a good quality to
be applied to the needs of techniques that have commercial value (Russel, Swan, Trebowicz, &
Ireland, 2016). The product is woven weaving cloth which is used for thermal and acoustic insulating
materials in construction and the automotive or geotextile industry(Patnaik, Mvubu, Muniyasamy,
Botha, & Anandjiwala, 2015).
Nonwoven fabric is a product that is made by spreading fibers in parallel, crossing or randomly
formed into a sheet of fabric using adhesive, or thermoplastic fibers that are conditioned with a
certain temperature and pressure (Patel & Bhrambhatt, 2011). Thermoplastic fibers or commonly used
adhesives are polyvinyl chlorides, polyamide, polyester, polypropylene, and polyethylene. The
adhesive used for making nonwoven fabrics must be adjusted to the basic material of the fabric used,
the melting point of the adhesive must be lower than the fiber to be made of cloth (P. K. Roy, 2011).
The adhesive used is plastic made from high- density polyethylene. High-density polyethylene plastic
is used because it has a low melting point compared to other adhesive materials which are equal to
135⁰C. Based on that, the study was taken about “The Making of Geotextiles From Raw Waste of
Wool Merino and Plastic Using The Thermal Bonding Method”.
2. Experimental
2.1. Materials
The material used is wool from merino sheep and polyethylene 2 plastic sheets which differ in
weight per one square meter. Where the fiber goes through the scouring process first by soaking it for
4 days and soaking it with kitchen salt for one day and then drying it to dry in the sun.
2.2. Method
This geotextile for wool fiber is made using the thermal bonding method, where wool fibers are
mixed with thermoplastic fibers. The adhesive used is plastic polyethylene with a content variation
of:
50% wool: 50% plastic HDPE
55% wool: 45% plastic HDPE
and 60% wool: 40% plastic HDPE.
The process of making the nonwoven fabric is carried out at the STTT Polytechnic Spinning
Laboratory in Bandung. The making of nonwoven fabric uses a prototype machine for making
nonwoven fabric with a thermal bonding method with hot rollers. Then the roller temperature is set
to 150⁰C because the adhesive material used has a melting point of 135⁰C. Then set the roller rotation
according to the specified parameters, which is set at a speed of 0.25 or 0.0028 m/s.
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3. Results
This section may be divided by subheadings. It should provide a concise and precise description
of the experimental results, their interpretation as well as the experimental conclusions that can be
drawn.
3.1. Weight per unit area
This test uses a standard SNI 3801: 2010 (Textiles - The method for testing for fabric weight per
unit length and weight per unit area). Based on the test, the results are presented in Table 3.1 which
can be seen below.
Table 1. Data of weight per unit area
Fabric Variation Weight per unit area
50 % wool, 50% HDPE 105.13 g/m2
55 % wool, 45% HDPE 116.78 g/m2
60 % wool, 40% HDPE 130.68 g/m2
It can be seen that the more wool content in the fabric, the higher the weight per unit area.
Regarding the content of a material in an object, Raymond Chang suggests that the more material, the
higher the mass will be (Chang, 2005). This can be seen in the nonwoven fabric that has been made.
As can be seen in the table, where it shows an increase which means that any difference in the weight
of the wool content on the fabric affects the weight per unit area of the fabric.
3.2. Moisture content and moisture regain
This test uses a standard SNI 8100: 2015 Textiles - Test method for moisture content (moisture
content or moisture regain). Based on the test, the results are presented in Table 3.2 which can be seen
below.
Table 2. Data of Moisture Content and Moisture Regain
Fabric Variation Moisture Moisture
Content Regain
50 % wool, 50% HDPE
55 % wool, 45% HDPE 6.96% 7.48%
60 % wool, 40% HDPE 7.09% 7.63%
7.69% 8.33%
Moisture content shows how much the fabric's ability to store vapor, the higher the value of the
moisture content, the higher the absorption capacity. The difference in the content of wool and plastic
in the fabric affects the moisture content of the fabric. As seen in the table, the more wool content in
the fabric, the higher the ability of the fabric to absorb water. As we know that wool fiber has a
moisture regain up to 14.4%(Soeprijono, 1973) and according to Vuni (2018) all types of polyethylene
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have hydrophobic properties (Setyowati, Ayu, Widodo, & Restu) which mean it cannot absorb water,
which with such properties can affect the absorbency of the fabric. Seeing when a wool fiber has
become a fabric with a plastic mixture, moisture regains on the fabric decreases by almost half. This is
because of the mixing done in heterogeneous mixing. Where according to Hardjono (2008) that
heterogenous mixtures are between two kinds of substances or more which constituent particles can
still be distinguished from each other. So that the properties and mixtures can be distinguished
(Hardjono, 2008). The properties obtained in the fabric are a combination of the two properties of raw
materials. So that when the content of wool is more than the plastic, then the resulting properties will
be more is the wool and vice versa.
3.3. Thickness
This test uses a standard SNI ISO 5084:2010 (Textiles – methods for testing the thickness of
textiles and textile products. Based on the test, the results are presented in Table 3.3 which can be seen
below.
Table 3. Data of thickness
Fabric Variation Thickness
50 % wool, 50% HDPE 62 mm
55 % wool, 45% HDPE 73 mm
60 % wool, 40% HDPE 81 mm
It can be seen that the more wool content or the less plastic content in the fabric will produce a
thicker fabric, as stated P.K. Roy (2011) that if the binding content is 10% of the total mixing, the fabric
structure is bulky, porous and flexible (Roy, Malik, & Sinha, 2011). Because the fabric produced is
bulkier, it will have a more thick effect on fabrics with only 10% plastic content.
3.4. Tensile strength
This test uses a standard SNI 0276:2009 (How to test the tensile strength and elongation of woven
fabric). Based on the test, the results are presented in Table 3.4 which can be seen below.
Table 4. Data of tensile strength
Fabric Variation Tensile Tensile
50 % wool, 50% HDPE Strength Strength
55 % wool, 45% HDPE (Length) (Width)
60 % wool, 40% HDPE 28.62 N 19.31 N
20.68 N 18.68 N
19.70 N 17.60 N
As seen in the table above shows that the more content of HDPE plastic on the fabric will
produce higher fabric strength. Wool fiber has a strength of 1.2-1.27 g/denier (Soeprijono, 1973) and
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according to Bally Ribbon Mills (2019), fiber polyethylene has a strength of 2.6-4.2 g/denier. It can be
seen that HDPE has higher strength than wool fiber, so when fabrics with HDPE plastic content, the
strength generated will be stronger. It can be proven that according to P.K. Roy (2011) the binding
content has a significant role in determining the properties of the fabric. If the binding content more
than 50% of the total mixing, the resulting fabric is like reinforced by plastic, whereas if the binding
content 10% of the total mixing, the fabric structure produced is hollow, porous and flexible with
relatively low strength (Roy, Malik, & Sinha, 2011).
3.5. Bursting Strength
This test uses a standard SNI 08-0617-1989 (how to test bursting strength knit fabric (diaphragm
method)). Based on the test, the results are presented in Table 3.4 which can be seen below.
Table 5. Data of bursting strength
Fabric Variation Bursting
50 % wool, 50% HDPE Strength
55 % wool, 45% HDPE 25.36 N
60 % wool, 40% HDPE 24.10 N
23.84 N
It can be seen in the table above that the plastic content will produce a strong fabric to break
down. This is because if more and more plastic content in the fabric, the fabric Struktur will be denser
and more solid compared to fabric with more wool content. According to P.K. Roy (2011), the binding
content has an important role in determining the properties of the fabric. If the binding content is
more than 50% of the total mixing, the fabric produced is like a fabric reinforced by plastic, whereas if
the binding content is 10% of the total mixing then the fabric structure produced is hollow, porous
and flexible with relatively low strength (Roy, Malik, & Sinha, 2011) Fabrics that are more hollow and
porous will be easier to be compared to fabrics with fewer capacities and pores.
4. Discussion
Non-woven fabric for geotextiles made from Merino Sheep wool and HDPE plastic can be
divided into 3 variations. Variations used are by distinguishing the content of plastic by varying the
plastic content by 50% (V1), 45% (V2), and 40% (V3). In preparation for making this fabric, the weight
of the plastic becomes a fixed variable so that the total amount of weight in each variation is not the
same, because the fabric made is likened to the size of a plastic that is 60 x 30 cm. So that there are
difficulties if the total weight of the overall variation must be the same, to overcome this thing the
amount of weight that can be adjusted is wool fiber so that each variation has a different weight of
wool.
When the production process takes place, some problems cannot be dealt with, the problem is
that there are variations in temperature on each roller. The rollers are set at 150⁰C, but the actual
temperature varies up to ± 30⁰C so that the heating of HDPE plastic on the fabric does not occur
evenly. Based on the results of correspondence with the lecturer, the factors that influence the uneven
temperature of the machine are due to the dirty elements for heating on the engine or the malfunction
of the heating elements contained in the rollers. After cleaning the heating element on the machine it
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did not affect the problem so that it could be concluded that there was a heating element inside the
rollers that did not work.
According to Roy et al. (2011) temperature is one of the factors that can affect the nature of the
products produced (Roy, Malik, & Sinha, 2011). Proven in the fabric there is a part of HDPE plastic
that melts perfectly and the part that has not melted is perfect. Both of these parts when the
evaluation was given the style produced far different results. The following is a comparison of results
data and quality standards for geotextile fabrics used for erosion protection.
Table 6. Comparison of test results with standard
Testing Unit V1 V2 V3 Class Class B Explanatio
A n
Tensile Strength (Length) N 28.62 20.68 19.70 200 90 X
Tensile Strength (Width) N 19.31 18.68 17.60 200 90 X
Bursting Strength N 25.38 24.10 23.84 320 140 X
It can be seen that the test results from fabric are made, none of them reached quality standards
for geotextiles that are applied to erosion protection on an industrial scale, this is due to the different
raw materials used, because the characteristics of the raw materials and the amount of composition
can also affect the results of fabric made.
Previously, research on the production of non-woven fabric for geotextiles from the wool fiber
was applied for erosion protection by Jan Broda (2017). It was found that the tensile strength of the
non-woven fabric was 0.67 kN / m2 (Broda et al., 2017 ) The following is a comparison of test results
with the results of previous studies.
Table 7. Comparison of test results with previous research
Testing Unit V VV Previous Explanati
1 23 Research on
X
Tensile Strength (Length) kN / 2.7 1.7 1.5 0.67
X
Tensile Strength (Width) m2 2 7 1 0.67
kN / 1.8 1.6 1.3
m2 4 0 5
It can be seen that the results of the fabric made have greater tensile strength than the previous
research, so it can be said that the results of the non-woven fabric made can be used as erosion
protection geotextiles.
5. Discussion
Based on the results of the tests that have been obtained, the test results that have been compared
with the standard can be concluded that waste of wool Merino and plastic can be made of non-woven
fabric with a prototype thermal bonding with hot calendaring method and can be used for erosion-
resistant geotextiles, but not for scale construction. The properties of the fabric are influenced by the
content of wool and HDPE plastic. Research needs to process holes in plastic sheets so that it can be
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made perfectly the porosity in the fabric, or use another adhesive like thermoplastic fiber and needs
to be done at a higher weight per unit area so that the test results can reach geotextile standards for
construction scale. The last one is the test that is done by all aspects of geotextiles.
References
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Proceeding Indonesian Textile Conference
(International Conference)
3rd Edition Volume 1 2019
http://itc.stttekstil.ac.id
ISBN : 978-623-91916-0-3
Interlaminar Shear Behaviour of UHMWPE (Ultrahigh
Molecular Weight Polyethylene) Based Composites
with Different Matrixes
Febrianti Nurul Hidayah 1*
1 Universitas Islam Indonesia
* Correspondence: [email protected]; Tel.: +62-8953-6332-6156
Abstract: Ultrahigh molecular weight polyethylene (Endumax®) based composite was treated to
investigate the route to improve interlaminar shear strength (ILSS) and its failure mechanism. The
failure mechanism of the composite was observed in this study by some failure tests such 3-point
bending on composite, and SEM analysis. To increase ILSS value of this UHMWPE based composite,
some routes were done by using different matrixes (HDPE film, LLDPE film, Epoxy resin, Styrene).
For overall practical approach, the failure mechanism detected in this study was caused by
delamination of UHMWPE fibrils. They were ripped apart during mechanical test that lead to
delamination of the composite. Numerous practical approach conducted, but the UHMWPE
composite would keep at low shear strength as long as nothing enhance the interaction between the
UHMWPE fibrils.
Keywords: Endumax®; UHMWPE; matrix; Interlaminar shear; Failure mechanism
ISBN : 978-623-91916-0-3
1. Introduction
Replacement of metals, especially steel and iron has been a popular topic for technical textiles
area which replaced with high performance fibres based composite. According to Ajayan and Tour,
composite is defined as material formed from two or more distinct materials, have desirable
combination of properties that aren’t found in the individual component [1]. The composite contains
two parts called reinforcement and matrix. Reinforcement is defined as strong integral and inert
component of a composite that is incorporated into the composite matrix to improve its physical
properties while the matrix material surrounds and supports the reinforcement materials by
maintaining their relative positions [2].
One of high performance fibres applied in composite systems that some research has been
conducted to improve its properties is ultrahigh molecular weight polyethylene (UHMWPE). The
UHMWPE fibers in general are used in armor, in particular, personal armor and on occasion as
vehicle armor, cut-resistant gloves, bow strings, climbing equipment, fishing line, spear lines for
spearguns, high-performance sails, suspension lines on sport parachutes and paragliders, rigging in
yachting, kites, and kites lines for kites sports [3]. Regarding to those application, at least three main
products of UHMWPE-based composite application will be related with this research are air freight
containers, portable shields, and wind turbines.
This composite was investigated in the term of mechanical properties with failure mechanism
such ILSS test (Interlaminar Shear Strength) to get the higher ILSS value. Failure mechanism is called
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also as destructive test include excessive deflection, buckling, ductile fracture, brittle fracture, impact,
creep, relaxation, thermal shock, wear, corrosion [4]. ILSS test is a special longitudinal three-point
bend test with fibers parallel to the length of the bend bar and the length of the bar being very small
[5]. ILSS is determined as most important parameter parameters in determining the ability of a
composite to resist delamination damage, which as key parameter for construction material as well.
Andreopoulos, Liolios, and Patriks conducted some similar research but just in mechanical
treatment by calendering to eliminate the microfibrillar morphology of the fibre and improve
interfacial bonding between fibre/matrix so that better compressive properties can be achieved in
reinforced resins [6]. Their research concluded that calendering did not significantly affect fiber
strength and only improved adhesive bonding slightly.
Based on the literature above, then this research aimed to improve the ILSS of UHMWPEbased
composite by observing some different orientations, calendaring conditions, and optimum glue used
either HDPE, LLDPE or reactive glue, then the samples will be evaluated with scanning electron
microscope and ILSS tested with failure mechanical tool thus the test results will be vary and the best
one could be concluded.
2. Experimental
2.1. Materials
To make a plate of composite, there should be needed reinforcement and matrix/resin. In this
study, main reinforce used was UHMWPE tapes (Endumax®) which obtained from Teijin B.V. (The
Netherlands), and four of matrixes were HDPE, LLDPE, Epoxy, and Styrene. The calendaring and
curing process for HDPE was set at 130ºC while LLDPE was at 120ºC and Epoxy was 70 ºC. Each
sheet was stacked until the thickness of approximately 4-5 mm, then pressed/cured in the press.
Variables for each treatment were differentiated by temperature, pressure and time. In the other
hand, Styrene was also used as alternative matrix. Approximately 95 gram of UHMWPE tape was
layered with mixture of 50 grams styrene, DVB, and BPO at room temperature. Then put them in
press, temperature was increased slowly to at least 85 °C to allow cross-linking process at 10 bar.
Apart of using HDPE or LLDPE film, epoxy was also used as matrix which applied by using
resin and hardener in ratio of 100:34 then rolled the mixture on UHMWPE (66% weight) and pressed
on 70ºC 10 bar for 16 hours. Each composite plates then prepared for tests by cutting them in different
dimension as requirement of the test with use of Eurolaser® cutter machine.
Table 1. Different practical approach on UHMWPE (Endumax®) tapes by varying the matrix system,
pressure and temperature into UHMWPE composite system based on each curing standard
Reinforcement Matrix/Resin Pressure Time
UHMWPE HDPE 50 bar (130 ºC) 10 min
UHMWPE LLDPE 50 bar (120ºC) 10 min
UHMWPE Epoxy 10 bar (80ºC) 16 hours
UHMWPE Polystyrene 10 bar (85ºC) 1 hour
2.2. Method
The standard reference used for ILSS test was ASTM D2344-48 (Test methods for Apparent
Interlaminar Shear Strength of Parallel Fiber Composites by Short-Beam Method). ILSS test was
applied by 3-point-bending test method with Instron® load cell of 1kN, 5 kN and 10 kN (span-to-
depth ratio was 4:1 and the loading speed was 2 mm/min). The thickness of sample was
approximately 5 mm and the width was 9 mm [7]. In other hand, this study also refers to ASTM D790
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(Test methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical
Insulating Materials). The bending properties test was applied by 3-pointbending test as well with
loading speed of 2 mm/min. The thickness of sample was approximately 5 mm and width of 13 mm
[8].
The test was continued by observing the samples after ILSS test on Scanning Electron
Microscope (SEM). The purpose of SEM analysis was to figure out the failure of bar whether
delamination caused by the matrix or reinforce itself. Sample was observed in different scales as well
(approximately 2-10µm) and analyzed the failure mechanism before and after bending applied. The
equipment used was ΣIGMA® series of Field Emission Scanning Electron Microscopes (FE-SEM)
delivers advanced analytical microscopy with the high performance from Carl Zeiss.
3. Results
As aimed in this study, investigating the mechanical properties of UHMWPE composites was
conducted by applying different matrixes (HDPE film, LLDPE film, Epoxy resin, Styrene). The
mechanical properties included interlaminar shear strength, shear modulus, bending strength and
bending modulus are shown below.
Table 2. Mechanical properties of each UHMWPE based composites with comparison of different
matrixes
UHMWPE UHMWPE/ UHMWPE UHMWPE
/HDPE LLDPE /Styrene /Epoxy
ILSS (MPa) 5.17 ± 0.04 5.42 ± 0.08 4.82 7.20 ± 0.02
Shear Modulus (MPa) 99 ± 3 148 ± 1 26 200 ± 7
Bending Strength (MPa) 78 ± 1 87 ± 1 55 ± 16 71± 2
Bending Modulus (GPa) 19.7 ± 0.6 19 ± 2 12 ± 2 10.9 ± 0.2
Density (g/cm3) 0.94 0.96 0.93 0.92
4. Discussion
The first strategy was to apply UHMWPE (Endumax®) as reinforcement, HDPE foil as matrix
system. When using UHMWPE and HDPE there was no very significant result, therefore further
practical approach was tried by laminating UHMWPE with LLDPE. The reason of choosing LLDPE
foil as alternative matrix was because three of them (UHMWPE, HDPE and LLDPE) are from
polyethylene but have different properties. The expectation was to see their differences on properties
and behavior in the form of composite system.
Based on scanning electron microscope observations, there were some representative images in
microscope scale what happened in the bar of UHMWPE/HDPE composite. This scanning electron
microscope analysis was done to determine the failure mechanism which indicates shear behavior as
well.
Figure 1. (a) UHMWPE/HDPE appearance on SEM with scale of 10 µm and magnification of 500times
shows two types of delamination and (b) scale of 100µm 100 times magnification : the delamination
first happened in the interphase of UHMWPE/HDPE then soon followed by delamination within
UHMWPE itself
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Based on Figure 1 above, there are two types of delamination/failure on UHMWPE/HDPE
composite. The first delamination is called cohesive delamination where the delamination happens
between two different material : UHMWPE and HDPE. The second delamination is called adhesive
delamination where this failure occurs within one material, in this case is UHMWPE tape. The only
delamination that did not occur in this phase is HDPE itself. Thus it could be also concluded that
UHMWPE has low adhesion towards HDPE. The conclusion could be first delamination started on
HDPE-UHMWPE interphase then soon after that cracked inside the UHMWPE.
The result of ILSS value of LLDPE as matrix was a bit higher than HDPE (see Table 2) where
UHMWPE/HDPE was only 5.17 MPa while UHMWPE/LLDPE was 5.42 MPa.
Based on both laminar matrix of HDPE and LLDPE, the expected higher number of ILSS could
not be achieved. Then styrene with variable of concentration was expected to give higher strength.
The use of styrene applied with DVB and BPO was approximately 20% of UHMWPE sheets weight.
Styrene experiment conducted because crosslinked-polystyrene has ever been used in one of the
studies as surface modification [9-12]. Therefore there is possibility it could be crosslinked in the
UHMWPE which fibrils located; to improve its strength.
Figure 2. Cross-linking between the styrene-divinylbenzene which later forms
poly(styrenedivinylbenzene) resin (-R represents ion exchange site located not R as R branch) [13]
It can be seen from Figure 2 above that reaction of styrene produces linear chain while
divinylbenzene cause this styrene chain to be cross-linked. The cross-linking should have enhanced
the mechanical stability. This reaction also included participation of free radical chain mechanism
which in this case used benzoyl peroxide as radical-producing initiator. When the mixture stirred and
heating applied (the press was set at 85°C), the polymerization happened and formed this cross-
linked polymer. Resin prepared in this way is called microporous due to its low porosity [14]. This
resin is relatively rigid, but unfortunately in this experiment result, the resin could not impact
positively to the property of composite because of its low adhesion towards UHMWPE.
Instead of increasing the value, styrene obtained lower value than previous approaches (4.82
MPa of ILSS). During the press, polystyrene was pressed out from the plate. It is possible that just few
of them left between the layers. Nevertheless, the samples were brittle but split apart due to low
adhesion among the sheets. Thus the experiment was not going to be continued for more polystyrene
percentage. Moreover, in scale of electron microscope, we could not see much polystyrene on sample
surface due to its low adhesion as mentioned above.
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Figure 3. SEM view of UHMWPE/polystyrene composite in the scale of 2µm with magnification 250
times which shows some of polystyrene coming out. It was quiet hard to search the location of
styrene because only very few of them appeared
Figure 3 above shows that few spots of polystyrene appeared to the sample surface. The possible
reason is because only few styrene left inside the composite due to press and poor adhesion toward
UHMWPE. From that figure also we can see that failures happened within
UHMWPE which fibrils of it got loose and delaminated. This indicates UHMWPE obtained its
adhesive delamination (failure within Endumax® tape) which this adhesive delamination also
happened in previous UHMWPE/HDPE experiment sample. Furthermore, we could see delamination
on following figure on the same spot but at higher magnification.
polystyrene Endumax ®
delamination
Figure 4. Sample appearance on SEM with scale of 10µm 1000 magnification which shows styrene
foam between the UHMWPE (Endumax®) layer where delamination also occurred
It is more obvious from figure above that polystyrene split out of UHMWPE which means the
matrix system was failed in this case. When the sample was cut, the fibrils of Endumax was easily
fallen apart and it contained polystyrene thus the polystyrene particles were also taken out from the
sample.
Due to lower number of strength using HDPE, LLDPE, polystyrene as matrix, another way was
introduced by epoxy resin. Epoxy resin is one of the most used matrix/resin in composite system from
practical studies, thus it was also chosen to see whether it will give positive influence on UHMWPE
composite or not. The experiment was set in 80°C (as the glass transition temperature). In results, the
final value of UHMWPE/Epoxy was the highest above all the practical approaches, which was 7.20
MPa of ILSS. The reason behind this phenomena was because of the adhesion of the epoxy was high
towards UHMWPE thus the plasticity of the composite increased. The failure mechanism of
UHMWPE/Epoxy in microscopic scale is shown in Figure 5 below. Figure 5 shows some delamination
between UHMWPE and Epoxy and within UHMWPE itself.
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delamination
Epoxy
Endumax ®
fibrils
Figure 5. SEM view of UHMWPE which laminated with Epoxy in magnification of 2,500 times with
scale of 2 µm, shows some delamination between UHMWPE and Epoxy and within UHMWPE itself
The failure on this composite mostly happened within UHMWPE since adhesion of Epoxy
towards UHMWPE was high. This could be shown as Figure 6 below that indicates the epoxy
adhesion higher than adhesion of UHMWPE fibrils.
Figure 6. Epoxy on UHMWPE layers view on SEM in scale of 2um and magnification of times and
zoomed into magnification of 25,000 times. It shows poor adhesion among fibrils of UHMWPE but
better adhesion of Epoxy towards UHMWPE
In conclusion of UHMWPE/Epoxy composite, the adhesion of Epoxy towards UHMWPE
(Endumax®) was good as shown on the SEM, while the fibrils of UHMWPE still ripped apart.
5. Conclusion
UHMWPE tapes were treated with different types of matrixes in composite system include
HDPE, LLDPE, polystyrene and epoxy, to obtain high value of ILSS and reveal the failure mechanism
behind it. The remark from the results of UHMWPE/HDPE and UHMWPE/LLDPE is there was no
substantial difference in ILSS. In other hand, polystyrene gave the composite of UHMWPE more
brittle properties but split apart due to low adhesion among the sheets thus gave the lowest value of
ILSS (4.82 MPa). Above all experiments, the highest number was approached by the
UHMWPE/Epoxy (7.20 MPa of ILSS) due to the adhesion of Epoxy towards UHMWPE (Endumax®)
was good as shown on the SEM, while the fibrils of UHMWPE still ripped apart. For overall practical
approach, the failure mechanism detected in this study was caused by delamination of UHMWPE
fibrils. They were ripped apart during mechanical test that lead to delamination of the composite. As
summary, in any practical approach conducted with various kinds of matrixes, the UHMWPE
composite would keep at low shear strength as long as nothing enhance the interaction between the
UHMWPE fibrils.
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