POLYETHER-POLYIMIDE THERMOPLASTIC ELASTOMERS .1. SYNTHESIS AND PROPERTIES

A series of polyether-polyimides based on polycondensation of poly(tetramethylene oxide)glycol di-p-aminobenzoate with different molecular weights (650, 1000, 2000) and benzenetetracarboxylic acid dianhydride (BTDA) or 3,3',4,4'-benzenetetracarboxylic acid anhydride (BPTDA) was synthesized. Infrared spectroscopy (IR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and stress-strain tests were used to follow the imidization process and to study the structure-property relations of this family of polymers. FTIR data showed that the imidization was completed after 6 h at 140-degrees-C, which is a much lower temperature than that required for polyimides synthesized from low molecular weight diamines. DSC and DMA results indicated that the block copolymer exhibited a well-phase-separated structure and had a broad rubbery plateau from about -70-degrees-C to 260-degrees-C, which varied with dianhydride type and hard-segment content. The BTDA series had enhanced mechanical properties compared to the BPTDA series. The excellent tensile properties of the polyether-polyimides suggest that they could be potentially used as heat-resistant thermoplastic elastomers.