Curing behavior, thermal, and mechanical properties of epoxy/polyamic acid based on 4,4′‐biphtalic dianhydride and 3,3′‐dihydroxybenzidine

Different synthesis routes were studied to obtain 4,4′‐biphtalic dianhydride/3,3′‐dihydroxybenzidine polyimide precursors (polyamic acids [PAAs]) with different inherent viscosities (IVs) and imidization degrees. The synthesized PAAs were introduced as a thermoplastic modifier into an epoxy (EP) resin. Different loadings of PAA were used to investigate the curing behavior, heat resistance, and mechanical properties. The onset curing temperature...