Atomistic prediction on the degradation of vinylester-based composite under chloride and elevated temperature

Abstract

Vinylester resin is widely used as matrix for fabricating glass fiber reinforced polymer in marine applications. Even though vinylester based material is understood to be durable in general, the interface between vinylester and the bonded additive can be degraded when subjected to various environmental conditions. Here, the degradation at vinylester/glass interface in chloride environment under elevated temperature is studied through molecular dynamics simulations. The atomistic model consists of a cross-linked vinylester matrix and an amorphous silica substrate. The results show that environmental condition of chloride and elevated temperature leads to the largest loss of interfacial adhesion, which correlates with structural and mechanical degradation of bonded interface. The degradation mechanism is indicated by reduced interfacial stress, decreased vinylester density close to interface, and formation of H-bond. Softened polymer matrix and deteriorated interface inhibit the stress transfer between fiber and matrix, eventually leading to deteriorated macroscopic properties. The performance of degraded vinylester is also compared with other polymer matrixes to provide guidance for designing more durable polymeric composites. This study provides fundamental information on interfacial deterioration in vinylester based composites, which forms the basis for predicting degradation of macroscopic performance.