EMAA as a healing agent for mendable high temperature epoxy amine thermosets

The encapsulation of the copolymer, polyethylene-co-methacrylic acid (EMAA) by polyetherimide (PEI) is used here to aid function as a healing agent in high temperature epoxy/amine composites. Importantly, PEI protected EMAA during processing while not inhibiting healing when required. Triethylenetetramine (TETA) and diethylene toluene diamine (DETDA) were used to functionalise EMAA further facilitating healing in some circumstances. Carbon fibre composites containing diglycidyl ether of bisphenol A epoxy (DGEBA) and DETDA were fabricated at 150 °C with variously modified EMAA and healing was evaluated according to mode I crack opening and interlaminar shear strength. No healing was observed for the un-modified EMAA, yet when coated with PEI, mode I loads and interlaminar shear strengths were restored to about 100% and 50% of their original values respectively. Functionalising EMAA showed further improvement for mode I failure though no trend was observed for ILSS.