Investigation of Nanomechanical Properties of the Interphase in a Fiber Reinforced Plastic Composite

Glass fiber reinforced plastic composites are widely used as structural materials. These two phase materials can be tailored to suit a large variety of applications. A better understanding of the properties of the fiber-matrix ‘interphase’ can enable more optimum design of composites. The interphase is a microscopic region around the fiber and hence nano-scale investigation using nano-indentation techniques is appropriate to determine mechanical property variations. In this study the atomic force microscope with the Hysitron indenter has been used to determine the variation of the elastic modulus across the interphase for different silane coated glass fiber reinforced polyester composites. A comparative study of the elastic modulus variation in the interphase is reported. The results are discussed in the light of the current limitations of the instrumentation and analysis.