Synthesis and properties of new hydroxyl-pendant aromatic polyimides derived from trimethylsilylated 4,4 '-diamino-3,3 '-dihydroxybiphenyl and aromatic tetracarboxylic dianhydrides

摘要

New phenolic hydroxyl-pendant aromatic polyimides were synthesized with the N-silylated diamine method in two steps: the ring-opening polyaddition of tetrakis(trimethylsilyl)-substituted 4,4'-diamino-3,3'-dihydroxybiphenyl to various aromatic tetracarboxylic dianhydrides, giving trimethylsiloxy-pendant poly(amic acid) triniethylsilyl esters, and thermal imidization. The hydroxyl-bearing polyimides were amorphous but insoluble in organic solvents. They had glass-transition temperatures greater than 370 degreesC and temperatures of 10% weight loss greater than 415 degreesC in nitrogen. The hydroxyl-pendant polypyromellitimide film had a high tensile strength and a high modulus of 310 MPa and 10 GPa, respectively. (C) 2002 Wiley Periodicals, Inc. [References: 20]