The Influence of Interfacial Structure on the Flexural Strength of E-glass Reinforced Polyester

Abstract

Abstract Simultaneous mechanical and molecular characterization of a composite system has been attempted with respect to the interface. The mechanical properties of an E-glass cloth/ y-methacryloxypropyltrimethoxysilane (γ-MPS)/bisphenol-A-fumarate polyester resin composite system were studied as a function of the amount of γ-MPS coupling agent present on the glass fiber surface. Fourier transform infrared diffuse reflectance spectroscopy was used to determine the amount and structure of γ-MPS on the glass. This structure consists of two clearly distinguishable regions: physisorbed layers of γ-MPS which can be dissolved by organic solvents, and chemisorbed layers which are insoluble. The physisorbed layers of γ-MPS reduced the strength of the polyester composite. A polymer blend consisting of siloxane oligomer of γ-MPS and bisphenol-A polyester was also investigated as a model of the silane interphase. Results from this model study are in agreement with the polyester composite data.