May - June 2016 17 Journal of the TEXTILE Association 1. Introduction Fibre reinforced composites have been widely used as materials for structural and non-structural applications in recent years. Synthetic fibres such as glass fibre, carbon fibre, and aramid fibre have replaced the heavy metallic bodies and is been used in automotive, ma- rine, aerospace, aircraft industries, and are now being used in structural and infrastructure application such as windmill, roof, bridge, girder, railway sleepers, and floating river walkway. These synthetic fibres are hav- ing excellent tensile, toughness and thermal resistance properties as well as hydrophobic nature. However, there are limitations like high manufacturing cost, non recyclability or biodegradability. To overcome these limitations alternatives of these fibres need to be sought out [1]. Renewable resources like natural fibres can provide good alternatives to synthetic fibres as a reinforcing material in composites. Plant-based natural fibres like jute, coir, sisal, pineapple, ramie, bamboo etc. have advantages of being low cost, easy availability, eco- friendly, lightweight, high stiffness over synthetic re- inforcing fibres. However, lack of good interfacial adhesion and poor resistance to moisture absorption have put limitation in the use of natural fibres in fibre reinforced composites replacing synthetic fibres. The limitation can be overcome by surface modification of natural fibre. The best properties of synthetic and natural fibres can be combined together in the same matrix to produce hybrid composite thus an optimal, superior but eco- nomical composite can be obtained [2]. Many researchers have attempted to combine synthetic and natural fibres in a single matrix to produce hybrid composites. Mohan et al reported that jute fibre could provide a reasonable core material in jute/glass hybrid laminate and found that glass skins not only enhanced the mechanical properties but also protected the jute core from weathering [3]. Pavithran and co-research- ers carried out detailed investigation on sisal/glass and coir/glass hybrid fibre reinforced polyester resin hy- brid composites giving emphasis to the effects of hy- brid design on properties such as tensile and impact strength and work of fracture. They found that hybridisation of sisal or coir with glass fibre could enhance the overall mechanical properties while im- proving the weathering characteristics of sisal or coir fibre [4]. John and Venkata Naidu compared untreated, alkali-treated and silane-treated sisal and glass fibre reinforced polyester hybrid composites. The alkali- treated hybrid composites showed better tensile strength than silane-treated and untreated hybrid composites due to removal of hemi-cellulose from sisal fibres which Sisal/Carbon and Jute/Carbon Hybrid Composites Dhanraj Desai, Girendra Pal Singh, Pallavi Madiwale, Sujata Pariti & R. V. Adivarekar* Department of Fibres & Textiles Processing Technology, Institute of Chemical Technology, Mumbai Abstract Fibre reinforced composites offers attractive mode for fabricating products with reduced cost, higher specific modulus, additional strength, corrosion resistance and excellent thermal stability in many cases depending on reinforcement material used to prepare composite. In the present work, attempt is made to fabricate hybrid composites using fibre mixture; Sisal/Carbon and Jute/Carbon, in different ratios and properties of hybrid composites are compared with 100 % Sisal, 100 % Jute and 100 % Carbon fibre composites. 3- amino-propyl-triethoxy silane was used to modify surface of fibres. The properties were found to be improved for silane treated fibre reinforced composites. The objectives of fabricating hybrid composite is to reduce cost of composite material by partial substitution of expensive synthetic fibre like carbon fibre by natural fibres like Sisal and Jute to reduce the environmental effect caused by the use of synthetic fibre. Keywords Sisal fibre, carbon fibre, 3-amino- propyl- triethoxy silane, hybrid composites * All the correspondence should be addressed to, Prof. (Dr.) R.V. Adivarekar, Head, Dept. of Fibres and Textile Processing Technology, Institute of Chemical Technology, Matunga, Mumbai-19 Email: rv.adivarekar@ictmumbai.edu.in PEER REVIEWED TECHNIACL TEXTILES