The Effect of Yarn Linear Density on Mechanical Properties of Plain Woven Kenaf Reinforced Unsaturated Polyester Composite

The Effect of Yarn Linear Density on Mechanical Properties of Plain Woven Kenaf Reinforced Unsaturated Polyester Composite

1,aMohd Pahmi Bin Saiman, 1,bMd Saidin Bin Wahab, 2,cMat Uzir Bin Wahit 1Department of Manufacturing and Industry, Faculty of Mechanical and Manufacturing Engineering,

Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia

2Center for Composites, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

[email protected], [email protected], [email protected]

Keywords: Kenaf Fibre, Plain Woven Fabric, Linear Density, Natural-based Composite

Abstract. To produce a good quality of dry fabric for reinforced material in a natural-based

polymer composite, yarn linear density should be in consideration. A woven kenaf dry fabric with

three different linear densities of 276tex, 413.4tex and 759tex were produced. The fabrics with

different linear densities were been optimize with the assistance of WiseTex software. The

optimized dry fabrics were infused with unsaturated polyester to produce composite panel using

vacuum infusion process. The composites properties were tested on the tensile strength, flexural

strength and the impact strength. The result shows that the mechanical properties of the composite

increased when the yarn linear densities increased.

Introduction

Natural based polymer composite has been accepted because of the beneficial of natural fibres such

as renewability, biodegradability and environmentally friendliness. There are many kinds of natural

fibres been used as reinforcing components such as sisal, coir, jute, kenaf, pineapple leaf and ramie.

Kenaf is one of the natural (plant) fibers used as reinforcement in Polymer Matrix Composites

(PMCs). Kenaf (Hibiscus cannabinus, L. family Malvacea) has been found to be an important

source of fiber for composites, and other industrial applications [1-2]. The interesting of kenaf

fibers is the properties which are low cost, lightweight, renewability, biodegradability and high

specific mechanical properties. It has superior flexural strength and excellent tensile strength which

make kenaf a good candidate for many applications [3].

There are three different geometrical shapes of PMC which are randomly oriented,

unidirectional and bidirectional to provide their mechanical and physical properties. Woven fabric

refers to the bidirectional reinforce material of PMC consists of an interlacing of two set yarn

known as warp yarn in vertical axis and weft yarn in horizontal axis. A woven reinforcement

exhibits good stability in the warp and weft directions and offers the highest cover or yarn packing

density in relation to fabric thickness [4]. To produce woven fabric reinforcement with the desired

requirement, three different factors which are weave design, fiber selection (linear density) and

fibre bundle spacing must be carefully selected to give the optimum fabric [5]. Linear density is a

yarn numbering system which is measured by weight per unit length of a yarn. Usually the main

unit system is in tex, decitex and denier. In linear density system, the finer the yarn, the lower is the

linear density. In a tex system, the unit referring to the weight of yarn in gram for a length of

1000meter (constant). The linear density of the yarn or fabric can be considered as a measure of the

average distribution of materials along the length of the structure [6].

In form of random reinforced fibres, many researchers have study on the effect of fibre fraction

towards the mechanical properties of the composite. However, in form of woven fabric, the yarn

linear density determined the fibre fraction which is the content of the fibers in the yarn cross-

sectional. Using three different linear densities with optimize woven plain structure; the effect of

mechanical properties on a natural-based composite was investigated.

Applied Mechanics and Materials Vols. 465-466 (2014) pp 962-966Online available since 2013/Dec/19 at www.scientific.net© (2014) Trans Tech Publications, Switzerlanddoi:10.4028/www.scientific.net/AMM.465-466.962

All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,www.ttp.net. (ID: 113.210.137.97, Universiti Tun Hussein Onn Malaysia, Batu Pahat, Malaysia-24/09/14,09:34:23)

Experimental

Materials. The kenaf yarn was supplied by Juteko Bangladesh Pvt. Ltd, Dhaka, Bangladesh with

linear density of 276tex, 413.4tex and 759tex. Unsaturated polyester resin (2597P-I) and methyl

ethyl ketone peroxide (MEKP) as the catalyst were provided by Wee Tee Tong Chemical Pvt. Ltd.,

Singapore.

Preparation of woven kenaf fibers specimen. As the parameters of the dry fabric were

determined, the kenaf yarns were self-woven into plain 1/1 (Fig. 1) using “Floor Loom”. To

determined the effect of linear density on the woven reinforced composite, the parameters are

considered in an optimize condition for plain fabric for each linear densities (Table 1). The WiseTex

geometrical model was used to predict the maximum limitation on the fabric count but due to the

usage of floor loom, only warp direction has reach the limit while weft direction is much lesser

(machine limitation). The prediction on the yarn data has shown the percentage of fibre volume

fraction (Vf) on yarn and the number of fibres (Nf) in the yarn cross-section. The prediction of areal

density of dry fabric shows a slight range of variation between prediction and actual. The Vf in form

of composites was calculated according to the equation (1) [7]:

Vf = n.m ÷ ρ.h (1)

Where n is the fabric ply number in the composite, m is the areal density of the fabric, ρ is the

density of the fiber (1.2g/cm3 [8]) and h is the measured thickness of the composite. There is only a

slight difference of Vf between prediction of dry fabric with actual Vf in a composite.

Fig. 1: Floor loom Fig. 2: Woven kenaf plain 1/1

Table1: Prediction and actual parameters of reinforce material properties.

Linear

density

[tex]

Fabric count Yarn Data

(prediction)

Areal density of dry fabric

[g/m2]

Dry fabric

(prediction)

Composites

(calculation)

Warp Weft Vf

[%]

Nf

Prediction

Calculation

Vf

[%]

Vf

[%]

276 9 6 72.5 121 463.7 462 29.7 27.58

413.4 7 5 71.4 179 552.7 479 28.5 24.70

759 5 4 72.6 315 759.2 690 28.5 23.00

Fabrication of composite panel. The woven kenaf/unsaturated polyester composite was

fabricated using vacuum infusion process (VIP). VIP is a closed mold with one side rigid mold and

another is flexible which is usually covered by vacuum bagging. The preform is infused with resin

using a vacuum pump system and flow evenly on a distribution media until it reach at the end with

excess resin flow into a resin trap. Three different panels were produce with different thickness

Applied Mechanics and Materials Vols. 465-466 963

(measured using a caliper); 276tex thickness panel 1.39mm, 413.4tex thickness panel 1.62mm and

759tex thickness panel 2.50mm.

Mechanical Properties Test. The test covered on the tensile test, flexural test and high speed

puncture impact test. Tensile test and flexural test was conducted using LLYOD, LR30K Universal

Tensile Machine and the test sample is only proceeding on the warp direction. The tensile test was

carried according to ASTM D3039 with each test used five specimens at a crosshead speed of

1mm/min. The flexural test used test method of ASTM D790-03 with a three-point loading system.

Five specimens for each panel were tested with calculated crosshead motion according to the

equation (2):

R = Z.L2 ÷ 6.d (2)

Where R is rate of crosshesd motion (mm/min), L is support span (mm), d is depth of composite

(mm) and Z is rate of straining of the outer fibre (mm/mm/min) which is equal to 0.01. The impact

test method used ASTM D3763 standard test methods for high speed puncture properties of plastics

using load and displacement sensors. The test apparatus used Hydroshot Shimadzu HITS-P10, High

Speed Puncture Impact Testing Machine with puncture velocity of 10m/sec. Three specimen for

each panel were tested for impact energy, J and converted to impact strength, kJ/m2.

Result and Discussion

Referring to Table 1, it shows that the Vf of all yarns are at the same range but the Nf of yarns are

different which 759tex is the highest followed by 413.4tex and lastly 276tex. When it is woven into

dry fabric and fabricate into a composite the Vf of the woven fabric are still at the same range. This

has shown that by optimizing the fabric count or yarn spacing (above prediction are considered as a

tight structure) the value for each linear density will gain a same range of Vf in form of woven

fabric. However, the content of the fibres are different as the 759tex have the highest amount of

fibres followed by 413.4tex and 276tex. This can be prooved by comparing with the areal density of

dry fabric and the thickness of the composite panel. The higher the fibers content in the yarn of the

woven fabric will make it more havier and thicker. Fig. 3 (a-c) shows an example of composite

thickness due to the influence of linear density.

Fig. 4 a) shows a prediction on the forces before fabric rupture while Fig 4 b) – c) is the result of

the tensile test on the composites. The graphs of prediction on dry fabric and the tensile strength of

the composite shows a same trend, when liner density increased the force or the stress increased

making it much superior in strength. This can be explain theoretically as strength increased

consistently with the increasing of fiber loadings [9]. From the prediction of the yarn data, 759tex

has 315 total numbers of fibres in the yarn cross-sectional followed by 413.4tex which is 179 and

276tex consists of 121 fibers. It shown that the amount of the packing fibers inside the twisted yarn

will determined the strength of the reinforce fabric to withstand the tensile load. Young’s modulus

or stiffness of the composite in a elastic stage of the composite shows a different trend. Increasing

the linear density resulted in decreasing of tensile modulus. The findings of the current study do not

support the previous study who reported that the Young’s Modulus increased as the tensile strength

Fig. 3: The influence of yarn linear density

of dry fabric towards composite thickness

(composites under microscope at 7x

magnification) a) 276tex b) 413.4tex and c)

759tex

964 4th Mechanical and Manufacturing Engineering

increased [9-10]. This will lead to an optional when selecting yarn size, which low linear density

will have high tensile strength with low tensile modulus and vice versa.

a) b) c)

Fig. 4: Prediction on dry fabric and tensile test with different linear density a) Prediction on the dry

fabric rupture, Force (N/mm) b) Tensile strength of composite c) Young’s modulus of composite.

Flexural properties represent the flexibility of the materials under static bending condition.

Higher flexural strength value indicated that the materials have a brittle nature, stiffer and high

value structure of high hardness [11]. Fig. 5 a) shows that 759tex has the highest stress to resist

deformation under load. The result has support the previous works where flexural strength increased

when the fibres content increased [12-13]. It is proven that the higher the fibres content, the stiffer it

is and making it much greater to resist any deformation.

Fig. 5 b) shows that the impact strength of 759tex composite is much superior compared to

413.4tex and 276tex composites. The covering area of the fabric for all yarn linear density is not a

factor as it all in optimum condition. This mostly influenced by the fibres loading which the greater

the linear density the higher the fibers content and increased the impact strength properties.

Previous study shows increment of impact strength when fibre loading increase [13-14].

Furthermore, the relation between the yarn packing density and the fabric thickness has increased

the energy absorbed by the composites.

a) b)

Fig. 5: a) Flexural strength of different linear density b) Impact strength of different linear density

Conclusions

In this study, the effect of high linear density of yarn will increase the mechanical properties of the

natural based composite. The selection of yarn linear density is important in optimizing the

properties of natural-based composite as it also related with the production process and its

application. The higher linear density of yarn means the higher the fibre loading inside the

composite which in relation with the mechanical properties of the composite. However, the

increment of the fabric linear density will increased the thickness and the weight of the composite.

High linear density of the fabric can be used as non-layered preform of composites to avoid any

damage tolerance of laminate composite such as intra-laminar crack or delamination due to

separation of plies.

Applied Mechanics and Materials Vols. 465-466 965

Acknowledgment

The authors are grateful to Faculty of Mechanical and Manufacturing Engineering and Advanced

Textile Training Centre, Universiti Tun Hussein Onn Malaysia for equipment and financial support,

to Faculty of Chemical Engineering and Centre for Composite, Universiti Teknologi Malaysia for

equipment and advice, to Department of Mechanical Engineering, Politeknik Seberang Perai for

testing equipment and Department of Metallurgy and Materials Engineering, Katholieke

Universiteit Leuven for WiseTex software.

References

[1] Karnani R, K.M., Narayan R., Biofiber reinforced polypropylene composites, Polym. Eng. Sci.

37(1997) 476.

[2] H.M. Akil, M.F.O., A.A.M. Mazuki, S. Safiee, Z.A.M. Ishak, A. Abu Bakar, Kenaf fiber

reinforced composites: A review, Material and Design. 32 (2011) 4107-4121.

[3] A.A.A. Rashdi, S.M.S., M.M.H.M. Ahmad, A. Khalina, Combined Effects of Water

Absorption Due to Water Immersion, Soil Buried and Natural Weather on Mechanical Properties

of Kenaf Fibre Unsaturated Polyester Composites (kfupc), International Journal of Mechanical

and Materials Engineering. 5 (2010) 11-17.

[4] Ogin, S.L., Textile-reinforced composite materials, in: S.A. A. Richard Horrocks, Subhash C.

Anand (Eds.), Handbook of Technical Textiles, Woodhead publishing limited: Abington

Cambridge, 2004, pp. 264-279.

[5] Ngai, T., Carbon-carbon composite, in: S.M. Lee (Ed.), Handbook of composite

reinforcements, Wiley-VCH, 1993, pp. 41-70.

[6] Ko, F.K., Tensile strength and modulus of a three-dimensional braid composite, in: Composite

materials: testing and design (seventh conference), ASTM special technical publication, 1986.

[7] Karahan, M., The effect of fibre volume fraction on damage initiation and propagation of

woven carbon-epoxy multi-layer composites, Textile Research Journal. 82 (2011) 45-61.

[8] M. Jawaid, H.P.S.A.K., Cellulosic/synthetic fibre reinforced polymer hybrid composites: A

review, Carbohydrate Polymers. 86 (2011) 1-18.

[9] Yicheng Du Jilei Zhang Jaesang Yu Thomas E. Lacy, J.Y.X.H.T.M.F.H.C.U.P., Jr., Kenaf Bast

Fiber Bundle–Reinforced Unsaturated Polyester Composites. IV: Effects of Fiber Loadings and

Aspect Ratios on Composite Tensile Properties, Forest Prod. J. 2010. 60 (2010) 582-591.

[10] Young Seok Song, J.T.L., Dong Sun Ji, Myung Wook Kim, Seung Hwan Lee, Jae Ryoun

Youn, Viscoelastic and thermal behavior of woven hemp fiber reinforced poly(lactic acid)

composites, Composites: Part B. 43 (2012) 856-860.

[11] Azrin Hani Abdul Rashid, R.A., Mariatti Jaafar, Mohd Nazrul Roslan, Saparuddin Ariffin,

Mechanical Properties Evaluation of Woven Coir and Kevlar Reinforced Epoxy Composites,

Advanced Materials Research. 277 (2011) 36-42.

[12] Y.A. El-Shekeil, S.M.S., K. Abdan, E.S. Zainudin, Influence of fiber content on the mechanical

and thermal properties of Kenaf fiber reinforced thermoplastic polyurethane composites,

Materials and Design. 40 (2012) 299-303.

[13] Gilles Sèbe, N.S.C., Calluma.S.Hill, Mark Hughes, RTM Hemp Fibre-Reinforced Polyester

Composites, Applied Composite Materials. 7 (2000) 341-349.

[14] Dhakal, HN. Zhang, ZY. Richardson, MOW Errajhi, OAZ, The low velocity impact response

of non-woven hemp fibre reinforced unsaturated polyester composites, Composite Structures. 81

(2007) 559-567.

966 4th Mechanical and Manufacturing Engineering

4th Mechanical and Manufacturing Engineering 10.4028/www.scientific.net/AMM.465-466 The Effect of Yarn Linear Density on Mechanical Properties of Plain Woven Kenaf Reinforced

Unsaturated Polyester Composite 10.4028/www.scientific.net/AMM.465-466.962

DOI References

[2] H.M. Akil, M.F.O., A.A.M. Mazuki, S. Safiee, Z.A.M. Ishak, A. Abu Bakar, Kenaf fiber reinforced

composites: A review, Material and Design. 32 (2011) 4107-4121.

http://dx.doi.org/10.1016/j.matdes.2011.04.008 [7] Karahan, M., The effect of fibre volume fraction on damage initiation and propagation of woven carbon-

epoxy multi-layer composites, Textile Research Journal. 82 (2011) 45-61.

http://dx.doi.org/10.1177/0040517511416282 [8] M. Jawaid, H.P.S.A.K., Cellulosic/synthetic fibre reinforced polymer hybrid composites: A review,

Carbohydrate Polymers. 86 (2011) 1-18.

http://dx.doi.org/10.1016/j.carbpol.2011.04.043 [10] Young Seok Song, J.T.L., Dong Sun Ji, Myung Wook Kim, Seung Hwan Lee, Jae Ryoun Youn,

Viscoelastic and thermal behavior of woven hemp fiber reinforced poly(lactic acid) composites, Composites:

Part B. 43 (2012) 856-860.

http://dx.doi.org/10.1016/j.compositesb.2011.10.021 [11] Azrin Hani Abdul Rashid, R.A., Mariatti Jaafar, Mohd Nazrul Roslan, Saparuddin Ariffin, Mechanical

Properties Evaluation of Woven Coir and Kevlar Reinforced Epoxy Composites, Advanced Materials

Research. 277 (2011) 36-42.

http://dx.doi.org/10.4028/www.scientific.net/AMR.277.36 [12] Y.A. El-Shekeil, S.M.S., K. Abdan, E.S. Zainudin, Influence of fiber content on the mechanical and

thermal properties of Kenaf fiber reinforced thermoplastic polyurethane composites, Materials and Design. 40

(2012) 299-303.

http://dx.doi.org/10.1016/j.matdes.2012.04.003 [13] Gilles Sèbe, N.S.C., Calluma.S. Hill, Mark Hughes, RTM Hemp Fibre-Reinforced Polyester Composites,

Applied Composite Materials. 7 (2000) 341-349.

http://dx.doi.org/10.1023/A:1026538107200 [14] Dhakal, HN. Zhang, ZY. Richardson, MOW Errajhi, OAZ, The low velocity impact response of non-

woven hemp fibre reinforced unsaturated polyester composites, Composite Structures. 81 (2007) 559-567.

http://dx.doi.org/10.1016/j.compstruct.2006.10.003