Development and characterization of flexible epoxy foam with reactive liquid rubber and starch

Flexible foams are prepared using carboxyl-terminated butadiene-acrylonitrile rubber (CTBN), diglycidyl ether of bisphenol A epoxy resin and a chemical blowing agent. Central composite design experiments are conducted to investigate the influences of three independent variables, i.e., the ratio of CTBN to epoxy resin, the amounts of curing agent (dicyandiamide) and blowing agent (azodicarbonamide), on the foam performances. After that, epoxy foams are also characterized for mechanical properties to explore the effects of the aforesaid ratio, accelerator type, starch and foaming methods. SEM analysis is used to evaluate the changes in cell characterizations.