Advanced Materials Research Vol. 585 (2012) pp 322-326 © (2012) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.585.322
PROPERTIES AND CHARACTERISTICS OF SISAL FIBRE REINFORCED COMPOSITE Ankita Sharma1,2, S. Suresh1,a, Amit Dubey2 1
Department of Chemical Engineering, Maulana Azad National Institute of Technology Bhopal, Bhopal-462 051, M.P., India. 2 Department of Applied Chemistry, Maulana Azad National Institute of Technology Bhopal, Bhopal462 051, M.P., India. a Corresponding Author E-mail:
[email protected] Key words: Sisal, Friction; Composites; polymer
Abstract Using the pin on disc wear testing machine the wear characteristics of sisal fibre composite of different content were studied and alignment of fibres in polymer composite were known by scanning electron microscopy. It was observed that when there was no fibre content, the wear was ~25 micron but when the fibre content made 10% to the polymer, the wear increased upto 100 micron and its increased 125 micron at 20% fibre content, after this there is sharp decrease in wear when the sisal fibre content was increased up to 40% and its again reached to 25 micron when the fibre content was increased up to 60% and again after increasing the fibre content 80% the wear gradually increased to 175 micron. Thus to have less wear the fibre content should be 60% in composite. Introduction Many years natural fibre composites are the alternatives of glass reinforced composites in many applications. Natural fibres such as banana, coir, sisal and jute have used to make composites which are used in consumer goods, low cost housing and other civil structures. Natural fibres have many advantages like low density, cheaper, acceptable specific properties and also they are renewable and biodegradable and its composites possess high strength and stiffness; good thermal; acoustic insulating properties and high resistance to fracture. However, these natural fibre/polymer composites had compatibility between the hydrophilic natural fibres and the hydrophobic matrix due to which it’s become necessary to use compatibilizers or coupling agents in order to improve the adhesion between fibre and matrix [1]. Sisal is the lignocellulosic plant which is found in America, Africa, and Asia. A sisal plant produces 200-250 leaves before flowering and its leaves contain approximately 700-1400 fiber bundles which are about 0.5-1.0 m [2]. Within the leaf three basic types of fibers are there: structural, arch and xylem fibers [2-3]. The sisal fiber constitutes of 65.8% cellulose, 12% hemicellulose, 9.9% lignin, 0.3% wax, and some water soluble compounds. In recent years the sisal fiber are used in many applications like making ropes, carpet, twines, mats, and handicraft articles beside this it is also used in making composites and in biogas production. Due to its good tensile strength, it is used to make composite with different polymers which increase the strength of the polymers. As the sisal fiber is cheap, biodegradable and eco-friendly; in present days it is used in many areas. Currently, plenty of research focused on the potential of sisal fibres reinforced composites. For using the fibre composites in many applications it is necessary that it had some mechanical properties like it should have flexibility, good tensile strength, and should have less wear property. As from the previous research it had been shown that the fibre increases the toughness of polymer than increasing the strength and modulus, and it is noted that sisal fibre composite had maximum toughness than other fibre i.e., approximately 1250 MNm-2 and its strength is 580 MNm-2 [4]. Wear can be defined as process in which there is dimensional loss of one solid with material loss when it interacts with another solid surface [5] and effect on wear resistance by fibre alignment in polymers. 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: 117.201.229.134-08/11/12,15:28:02)
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In present work, the chemical and structural property of sisal fibre improved with modification, and used to reinforce resin based composite. To study surface morphology, wear resistance property, FT-RAMAN of untreated fibre and fibre-reinforced composite on which various effect will be noticed. Experimental procedure: Material required: Sisal fibre decorticated (sisal decorticator which can extract 300 to1400mm fresh sisal leaf into fibre) from leaves and cleaned with ethanol to make it free from impurities, cold setting agent(from Mctech company) which content powder and liquid solidifying agent (by mixing the powder and liquid, polymer is formed) and the cylindrical mould. General procedure: Ethanol washed sisal fibre is chopped into small pieces. The cold setting agent, (5 gm of powder and 5 ml of liquid) mixed with various proportion of sisal fibre, i.e., 10%, 20%, 40%, 60%, 80% and one without fibre. The mixture then put into mould of size 12 mm×25 mm. After solidifying it is removed from the mould and polished. Then the sample is tested and characterised in wear resistance tester, RAMAN and SEM. Wear resistance test: Wear resistance test will be performed by pin on disc wear testing machine, magnum engineers, model no.-TE-100LE with 2kg load, 48 mm trap radius and 125 rpm parameters. The wear test is conducted for 10 min. In this study the variation of wear rate with respect to time is examined. FT-RAMAN: FT-RAMAN spectra (wavelength is 785 nm, Delta NU,RAMAN spectrometer made in USA) with laser power 10 mV and integration time 25 sec used to examine the sisal-reinforced composite. SEM: The sisal-reinforced were characterised using scanning electron microscope (SEM, JEOL JSM-6390) to characterised its surface morphology. As the composite is non-conducting, so to analyse in SEM first the sample should be made conducting by coating it with gold and silver. For gold coating, coating unit is used, and samples are kept for 30 sec. Result and discussion: The various characterizations of polymer composite were performed using SEM, Wear tester and Raman Spectra. SEM of the composites is shown in Fig. 1 (a-f). In composite process, sisal fibres were compressed along the radial direction and strain energy be deposited. During the moulding process, the resin on the sliding surface was frayed off, and the anamorphic fibres tend to expand to the original size, as showed in Fig. 1 (a-f). It was also shown that the surface of polymer is closely packed but when the fibre is added to the polymer the surface area of fibre increased and the alignment of fibre also tightly bound the polymer thus the rate of wear decreases [6].
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(e) (f) Figure 1. SEM of sisal fibre-reinforced composite where (a).composite without fibre; (b). composite with 10% fibre; (c).composite with 20% fibre; (d). composite with 40% fibre; (e). composite with 60% fibre; (f). composite with 80% fibre. According to the literature survey, in sisal fibre-reinforced composite, sisal fibre provides the high friction coefficient and also strengthens the composite body, it is also noted that optimum ratio of polymer: sisal should be there to have minimum wear rate [6]. In previous research, wear rate and friction coefficient were measured with temperature but there is limitations with temperature condition as at high temperature (>250oC) the sisal fibre decomposes (friction properties of sisal fiber reinforced resin brake composites). In present work, the wear rate and friction coefficient were measured with time and Fig.2 shows the variation of wear rate with time, it was noted that that wear rate increases when the fiber added to composite up to certain limit then a sharp decrease in wear rate was observed when sisal fiber concentration increases to 60% and then its increases with sisal concentration. The sisal fibre’s have the cell vacuum inside. Thus when the rigid asperity on the friction couples contact the sisal fibre, the fibre compressed elastically, the reason behind it is the cell vacuum which we mentioned above. Thus when the entire vacuum had compressed to minimum size the stress limit of sisal fibre achieved and after that the cell rupture and the wear rate will increase further [6]. This shows that at optimum ratio of polymer: sisal there is minimum wear rate as if the concentration of polymer is more than the surface lack fiber on the surface of wear couple thus matrix abraded easily and if fiber is more than polymer concentration is not enough to wrap fiber and thus the fiber will not coagulated firmly which also result in matrix abrasion (Friction properties of sisal fiber reinforced resin brake composites). Table 1 shows weight before and after the wear test. Raman spectra of composite are shown in Fig. 3 in which the peaks which was found in sisal fibre are found when the spectra of sisal fibre-reinforced composite where compared with the composite without fibre then we found that in composite without fibre, 10% fibre content composite and 20% of fibre content composite has very intense peak at wave number 379, 490, 607, 813, 918,
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1000, 1074, 1130, 1463, 1730 ʋcm-1. At 813ʋcm-1 the peak is very intense [7]. When the fibre content is increases the peak intensity decreases and broad line is shown. This shows that the peak is of polymer and not from fibre, so when the fibre density increases the peak intensity is decreases. Table 1. Variation in sisal fibre with cold setting agent on composite materials. Amount of sisal Amount of cold Diameter Weight of composite (g) fibre (g) setting agent of the composite Amount Amount Before wear After wear test (mm) of powder of liquid test (g) (ml) 0.0 5 5 12.91 3.245 3.240 0.1 5 5 12.68 3.089 3.086 0.2 5 5 13.62 3.233 3.230 0.4 5 5 11.70 2.893 2.890 0.6 5 5 13.18 3.580 3.579 0.8 5 5 12.54 3.069 3.066 From table 1 it is cleared that the weight loss is constant in all cases only there is difference in wear rate with variation of time. 200
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Figure.2. Wear rate of composite where A2 is composite without sisal fibre; A4 is composite with 10% sisal; A6 is composite with 20% sisal; A8 is composite with 40% sisal; A is composite with 60% sisal, C is composite with 80% sisal. Conclusions In present work, the chemical and structural property of sisal fibre were improved with modification, and used to reinforce resin based composite. The following conclusions were made with the results: (1) The friction and wear properties of sisal composites up to the optimum point with the proportion between resin and sisal fibre is 3:2; (2) Strain energy deposited in sisal fibres is the main factor that made its reinforced composites with prefer high friction factor and low wear rate; (3) The sisal has the potential to be an ideal substitute for good polymer composites. (4) The RAMAN spectra shows that the peak intensity decreases as the content of fibre increases in the composite. Thus the peaks were sensitive to polymer in composite. (5) The weight loss is very less after wear i.e., approximately 0.003g. (6) The sisal has the potential to be an ideal substitute for good polymer composites.
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Figure 3. RAMAN Spectra of composite where A2 is composite without sisal fibre; A4 is composite with 10% sisal; A6 is composite with 20% sisal; A8 is composite with 40% sisal; A is composite with 60% sisal, C is composite with 80% sisal. Acknowledgment The authors wish to thank Handloom and Handicraft Rural Development Department, Government of Madhya Pradesh, India for given R&D Project to strengthen sisal fibre area and also thanks to MANIT Bhopal to carry out experimental work and others. One of author (Dr. S. Suresh) sincere thankful to Dr. C. Sasikumar for given valuable suggestion in this work. References: [1] A.V. Ratna Prasad, K. Mohana Rao, Mechanical properties of natural fibre reinforced polyester composites: Jowar, sisal and bamboo, Materials and Design 32 (2011) 4658–4663. [2] F. de Andrade Silva , N. Chawla , R. D. de Toledo Filho, Tensile behavior of high performance natural (sisal) fibers, Composites Sci. Tech. 68 (2008) 3438–3443. [3] S. Suresh, Preparation of nanocelluloses from sisal plants (Agave Sisalana). Winter School on Chemistry and Physics of Materials, jointly organized by International Centre for Materials Science at Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore and Cambridge University, UK Dec 5-10, 2011. [4] C. Pavithran, P. S. Mukherjee, M. Brahmakumar, A. D. Damodaran, Impact properties of natural fibre composites, J. Materials Sci. letters 6 (1987) 882-884. [5] Information on http://en.wikipedia.org/wiki/Wear [6] X. Xin, C.G. Xu, L.F. Qing, Friction properties of sisal fibre reinforced resin brake composites, Wear 262 (2007) 736–741. [7] H.G.M. Edwards, D.W. Farwell, D. Webster, FT Raman microscopy of untreated natural plant fibres, Spectrochimica Acta Part A 53 (1997) 2383-2392.
