Cure behaviors and thermal stabilities of tetrafunctional epoxy resin toughened by polyamideimide

The effect of polyamideimide (PAI) content on the cure behaviors and thermal stabilities of 4,4′-tetraglycidyl diaminodiphenyl methane (TGDDM) epoxy resin/polyamideimide (PAI) blends was investigated. The experimental results revealed that the main exothermic peak and cure activation energy ( E a ) of the blends decreased with increasing PAI content, presumably because the curing reaction was accelerated by the presence of secondary amine groups of the PAI backbone. The decomposition activation energy ( E d ) of the blends was maximized at 5 phr PAI and decreased above this content; this was attributed to the short-chain structural network in TGDDM/PAI blends, which was derived from etherification and chain-scission reactions caused by the secondary amine of PAI.