Abstract
Long chain polyacid anhydrides with side chains were found to be the curing agent having good workability for flexible epoxy resins, because of the polyanhydride were liquid at room temperature.
The epoxy resins cured with these polyanhydride studied were very flexible and had good thermal shock resistance, electrical property, and low water absorption.
The mixt. curing agent of the polyanhydride and the widely used anhydride such as methyl hexahydrophthalic anhydride was also studied, because the polyanhydride cured epoxy resin was too flexible. The ratio of the polyanhydride in the mixt. curing agent decreased with increased glass transition temperature of cured resin. As a result, the mixt. acidanhydride cured resin system were flexible above 0.7 of polyanhydride in curing agent, tough between 0.7-0.2 and brittle up to about 0.2.
