The Pacific Journal of Science and Technology –463– http://www.akamaiuniversity.us/PJST.htm Volume 13. Number 1. May 2012 (Spring) Effect of Concentration of Coconut Shell Ash on the Tensile Properties of Epoxy Composites. P.E. Imoisili * ; C.M. Ibegbulam; and T.I. Adejugbe Engineering Materials Development Institute, Akure, Nigeria. E-mail: patrickehis2002@yahoo.com * ABSTRACT Particulate filled polymer composites are becoming attractive because of their low cost and wide applications. To determine the possibility of using agricultural waste materials as reinforcing fillers in thermosetting polymer composite, the effects of coconut shell ash (CSA) concentration on the tensile properties of polyester composite was investigated. Five filler concentrations (viz. 5 to 25 weight %) were fabricated, test results shows that tensile strength, elastic modulus, and micro- Hardness of the composite increases with increase in filler concentration, while percentage elongation and load at break decreases with increase in filler concentration. Thus CSA can be use as reinforcing filler in epoxy composite. (Keywords: coconut shell ash, CSA, epoxy composite, reinforcing filler, tensile properties) INTRODUCTION Epoxy resins are one of the most important classes of thermosetting polymer which are widely used as matrices for fiber-reinforced composite materials and as structural adhesive (Shangjin et al., 2007and Zhikai et al., 1987). Epoxy are amorphous, highly cross-linked polymer and this structure result in the materials possessing various desirable properties such as high tensile strength and modulus, uncomplicated processing, good thermal and chemical resistance, and dimensional stability (Zhikai et al., 1987) one of the successful method of improving the toughness of epoxy resin is to incorporate a second phase of dispersed rubbery particle into the cross-link polymer (Drake et al., 1982, Riffle et al., 1983, and Yorkitis, 1994). Because the addition of rubbery materials to epoxy resin has been shown to lower their glass transition temperature (Tg) and thermal and oxidative stability, high performance thermoplastics have been employed to toughen epoxy resin in recent years (Shangjin et al., 2007 and Zhikai et al., 1987). Using natural filler to reinforce the composite materials offers the following benefit in comparison with mineral filler (Herrara-Franco et al., 1997 and Maulida et al., 2000), strong and rigid, light weight, environmental friendly, economical, renewable, and abundant resource. However, they have the disadvantage of degradation by moisture, poor surface adhesion to hydrophobic polymers, non-uniform filler sizes, not suitable for high temperature application among others (Belmares et al., 1983). Research is proceeding to develop composites using various recycled wastes (Son JI et al., 2001), especially in developing composites using most environmentally friendly agro-wastes as reinforcing fillers and thermosetting polymers as matrixes. Recent investigations of polymer-based composite materials have opened new routes for polymer formulations and have allowed the manufacture of new products with optimal properties for special applications (Karnani et al., 1997 and George et al., 2001). In most cases, these composites improve the product design and reduce the material and energy consumption. A number of natural occurring fillers and fiber in composite have been studied in the past. These include wood fillers (Gattenholm et al., 1993) wheat straw, almond husk, ash rice husk (Ismail et al., 2001 and Saroja Devi et al., 1998), pineapple leaf (Mishra et al., 2002), coconut fruit fibers(Sergio et al., 2005). Wood-based fillers derive from oil palm wood flour (Fuad et al., 1998), etc. These fillers introduce some advantages compared to traditional inorganic fillers, including their renewable nature, low density, nonabrasive properties, reasonable strength, and stiffness (NeusAnglès et al., 1999).