Dynamic-mechanical properties of natural fiber-reinforced plastics: The effect of coupling agents

The investigated composites were epoxy resins reinforced with jute fibers. The jute fibers were modified with an ep oxy-functional gamma-glycidoxypropyltrimethoxy-silane (A-187), which works as a coupling agent between the fiber and the matrix. The use of a coupling agent distinctly influences the mechanical properties of the composite. Dynamic modulus was doubled; correspondingly the damping was reduced approximately 50 percent and the Wohler curves showed fatigue limits increased about 20 percent. Finally, the application of the coupling agent caused a reduction of the moisture influences on the mechanical properties. Tensile strength, tensile modulus, and fatigue strength under repeated tensile stress were reduced up to 30 percent. This tendency was not proven by the results for flexural strength and flexural modulus.