Polylactic acid (PLA) is a rigid thermoplastic that has a special interest as a matrix in composite
materials. PLA is a highly versatile biopolymer and is highlighted because it is derived from a renewable
resource such as corn. PLA can be processed by injection molding, blow molding, and film forming [3].
Although the mechanical properties of PLA suited for some industrial applications, it is considered too
brittle for many commercial applications. It is possible to overcome the brittleness by combining it with
other materials. Natural fiber as a replacement to synthetic fiber in polymer matrix offers a good
mechanical performance and eco-friendliness. The application of natural fiber based composites is
increasing rapidly. The combination of interesting mechanical and physical properties together with their
environmentally friendly character has aroused interest in a number of industrial applications [4-6].
The quality of the fiber-matrix interface is significant for the application of natural fibers as
reinforcement for polymer matrices. In order to improve the compatibility between hydrophobic
thermoplastics and hydrophilic cellulosic fibers, many chemical and physical surface treatments have
been applied to achieve high performance natural fiber reinforce composites. A variety of silanes have
been applied as coupling agents in the natural fiber composites to promote interfacial adhesion and
improve the mechanical properties of composite [7-9]. However, natural fibers require low processing
temperatures due to possibility of their thermal degradation. Research study on application of
thermosetting resin as the surface treatment of natural fiber to enhance the thermal stability during high
temperature process has been reported [10]. Therefore, the effect of fiber content and processing
parameters on the properties of natural fiber reinforced composites are particularly significance. The
suitable fiber content and processing parameters must be carefully selected in order to get the optimum
property of composite. Many research works have been studied the utilization of natural renewable
resources as the reinforcement in polymer composites [11-14]. In this study, bamboo fiber, vetiver grass
fiber and coconut fiber were selected as the reinforcement for PLA composites. The effects of flexible
epoxy surface treatment on tensile property of different natural fiber reinforced PLA biocomposites were
investigated.