Abstract: | The synthesis of a new class of block polymers that contain alternating polyimidothioether “hard” blocks and polysulfide elastomer “soft” blocks is described. Compositions with 70% and greater polysulfide component are solvent-resistant, thermoplastic elastomers exhibiting room temperature tensile strengths of up to 1500 psi and ultimate elongations of nearly 800%. The physical properties are a strong function of test temperature due to relatively short polyimidothioether blocks, 850 ≤ M?n ≤ 3500 g/mole. These short polyimidothioether blocks were necessary to minimize degradation of the polysulfide elastomer blocks during thermal processing at temperatures ~100°C above the “hard” block domain Tg. |