Heat‐resistant thermosetting polyimide matrix resins containing keto, ether, hexafluoroisopropylidene linkages and maleimido‐ and nadimido‐ end capped groups

摘要

AbstractVarious heat‐resistant thermosetting polyimides containing hexafluoroisopropylidene and keto and ether groups suitable for fiber‐reinforced composites development have been synthesised by thermal polymerization of maleimido and nadimido end capped polymer precursors. Thermal polymerization involving addition reactions was performed at 225°C for 1.5 h and post‐curing at 290°C for 0.5 h. Tough polymers XVIII to XXIII were obtained. The thermal polymerization was monitored using infrared spectroscopy. The polymer precursors were characterized by IR,1H‐NMR, and elemental analysis. The synthesized polymers were evaluated for thermal stability using dynamic thermogravimetric analysis (TGA). All the polymers showed thermal decomposition temperatures in the range of 430–435°C in nitrogen and in air. The char yield of the polymers was in the range of 60–67 in nitrogen at 800°C. This study indicated that thermally synthesized polymers from hexafluoroisopropylidene, keto, and ether containing polymides are potential candidates for the development of advanced materials for aerospace and high‐tech applications. © 1993 Jo