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 (Ea) 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 (Ed) 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.[graphic not available: see fulltext]