Inclusion of a thermoplastic phase to improve impact and post-impact performances of carbon fibre reinforced thermosetting composites - A review

Infusion processing methods have become a popular manufacturing alternative to the autoclave procedure to meet the increased demand for high-performance composites with shorter production times and lower cost. These processes are primarily limited to low viscosity, thermosetting matrices that are inherently brittle, and hence are susceptible to impact damage. It has been shown that introducing a thermoplastic modifier to create a "three-phase composite" can improve the ability of the laminate to resist damage formation and growth, and enhance a damaged laminate's structural performance. A comprehensive review is presented herein of the state-of-the-art on the incorporation of a thermoplastic phase into a fibre-reinforced thermosetting composite laminate to improve its damage resistance and tolerance properties when subjected to a low-energy impact. Several material properties govern the response of a laminate to an impact event, and for this reason, a discussion on the impact damage process and post-impact performance is also presented. Techniques from two main areas of toughening are considered - namely, bulk resin modification and interlaminar toughening. The improvements in laminate performance brought about by the thermoplastic additive are discussed, and each technique is assessed based on its suitability for inclusion in infusion manufacturing processes.