Synthesis and some properties of hyperbranched polyaryleneetherketone (PEK)-co-polybenzobisthiazole (PBZT)-co-hyperbranched polyaryleneetherketone (PEK) ABA triblock copolymers

摘要

The aromatic-heterocyclic rigid-rod polybenzobisazoles (PBX) such as polybenzobisthiazole (PBZT), polybenzbisoxazole (PBO), and polybenzobisimidazole (PBI), well known for their excellent thermal and mechanical properties as well as their interesting optical and electronic characteristics, continue to be of interest to advanced materials research. A great drawback for PBX is their insolubility in common organic solvents, thus limiting the processing options. With the exception of a few sulfonated PBI and related copolymers (water-soluble), PBX are generally only soluble in strong acids such as methanesulfonic acid (MSA) and sulfuric acid. These polymers are, in general, prepared from heterogeneous polycondensation in mild acid such as polyphosphoric acid (PPA, 83% assay) at elevated temperature (Scheme 1).