Natural fibers are considered as an alternative to glass fibers for use in composites as reinforcing materials. The advantages of natural fibers over glass fibers are low cost, low density, easy availability, low energy content and recyclability [1]. The industrial use of natural fibers as reinforcing agent in composite materials started at the beginning of the 20th century with the manufacturing of sheets, tubes and pipes for electronic purposes. Some limitations of natural fiber composites are poor wettability, incompatibility of fibers with some polymeric materials and high moisture absorption of fibers, make them undesirable for certain applications. The main problem often encountered is the fiber and matrix adhesion problem, due to the incompatibility between hydrophilic nature of natural fibers and hydrophobic nature of polymeric matrices. Chemical modification of fibers is a common method for modifying the fiber surface which enhances the bonding between a natural fiber and a polymeric matrix [2]. Several articles have been reported on composites based on natural fiber and their surface modification such as bagasse [3], Moroccan hemp [4], Sansevieria cylindrica [5], banana [6] and [7], sugar palm [8] and coir [9] as reinforcing materials in polymeric matrices. The preliminary studies of coconut sheath fibers have been reported in literatures [10] and [11].