Carbon fiber textile composites using highly-polymerized thermoplastic epoxy: effect of molecular weight of epoxy on the mechanical performance of composites

The purpose of this study is to reveal the effect of resin molecular weight on the mechanical properties of carbon fabric reinforced thermoplastic epoxy composites (CFRTP). An extensive experimental campaign allowed understanding the influence of the thermoplastic resin with weight-average molecular weight (Mw) ranging from 14,000 to 117,000. Different loading conditions were applied, including quasi-static and cyclic three point bending and tensile loadings. Moreover, fiber-matrix adhesion and interlaminar fracture toughness were measured by micro-droplet and End Notched Flexure (ENF) mode II fracture tests. The mechanical responses highlighted the considerable improvements of the composite performances for thermoplastic epoxy with high polymerization (high molecular weight). It is also shown that an excessive polymerization, greater than 60,000 Mw, is not necessary for composite performance.