Recently, the interest in using natural fibers as reinforcement in plastics has increased dramatically. With regard to the environment aspects, it would be very beneficial if natural fibers could be used instead of synthetic fibers as reinforcement in some structural
applications. Crude oil price have soared in recent years, doubling from 2003 (USD 28.1) till 2006 (USD 61.24). Accordingly, the cost of synthetic fibers keeps increasing. On the other hand, the natural fibers are inexpensive and do not cause allergic reactions in the human body. Moreover, the advantages of such fibers over man-made fibers include low density, low cost, recyclability, and biodegradability [2–4]. These advantages make natural fibers a potential replacement for glass fibers in composite materials.
Many researchers have investigated the strengthening effects on the natural fillers reinforced epoxy and various polymer composites. However, the presence of hydroxyl and other polar
groups in the natural fibers lead to weak interfacial bonding between the fibers and relatively hydrophobic polymers; these properties should be improved by interfacial treatments.