SYNTHESIS AND MISCIBILITY STUDIES OF RODLIKE FLEXIBLE POLYIMIDE MOLECULAR COMPOSITES VIA PARA-PARA LINKED AROMATIC POLY(AMIC ESTER) PRECURSORS

Para-para linked aromatic poly(amic ester) precursors of rodlike polyi mide (PI) BPDA-PDA and polyetherimide (PEI) HQDPA-ODA were synthesized . The para-para linked poly(amic ester)s were employed in this work to obtain, in theory, full-imidized polyimides. The two precursors were mixed by dissolving them in N, N'-dimethyl acetamide and subsequently coagulating in methanol. After thermal imidization, the miscibility be haviour of the resulting composites has been studied by means of dynam ic mechanical analysis (d.m.a.) and differential scanning calorimetry (d.s.c.). The composites show a single glass transition temperature (T -g) at both d.m.a. and d.s.c. in which the T-g increases with increasi ng PI content. These Tg values are reproducible in repeated heating cy cles, suggesting the true miscibility of the blends. (C) 1997 Elsevier Science Ltd.