Prediction of chain-growth polymerisation of vinyl ester resin structure at the carbon fibre interface

Abstract Carbon-fibre reinforced polymer composites play an important role in the aerospace, marine, construction and automotive transport industries due to their light weight and robust mechanical performance. The interface between the resin matrix and the carbon fibre surface is a critical zone, where poor interactions at this interface may give rise to a point of failure in the composite. It is therefore critical to develop structure/property relationships for these interfaces at the molecular level. This is challenging to achieve using experimental approaches alone, and molecular simulations can provide complementary data to achieve this goal. Although substantial progress has advanced such understanding of the interface based on epoxy resins, the analogous vinyl ester resin interface is relatively under-explored in terms of molecular simulation, despite their widespread utility in many applications. This may be due to the additional complexity inherent to the challenges of modelling chain-growth polymerisation at the interface. In this work, molecular simulations are used to polymerise a vinyl ester/styrene resin in the presence of a pristine fibre surface. The evolution of the polymer chains was characterised in terms of chain length, composition, and distance from the surface plane. The interfacial shear stress was calculated using a computational a pull-out test, revealing poor interfacial integrity, consistent with recent experimental data. These findings provide a solid basis for future investigations to explore surface functionalisation strategies of the fibre surface to best tailor this critical interface in vinyl-ester resin carbon fibre composites.