Abstract

The poly(Friedel–Crafts) reaction between benzene-1,2,4,5-tetracarboxylic dianhydride and diphenyl ether gave carboxylic acid functional polyarylates (PEKK-COOH) that were soluble in polar solvents such as NMP and DMF. The carboxylic acid functional polymers were thermally stable up to 400 °C. PEKK-COOHs in DMF or NMP solution, dispersed in paraffin oil, were cross-linked by reaction of the pendant carboxylic groups with bisphenol-A diglycidyl ether. Insoluble networks were formed by reaction of between 45 and 95 mol% of the carboxylic acid groups. Although regular particles were formed initially, upon drying they formed irregular particulate aggregates that could not be redispersed back to the primary particles. The networks showed a degradative weight loss around 150 °C, which was caused by dehydration from the 2-hydroxypropyloxy group. Further curing of the particles at 160 °C produced a material which did not show any obvious differences in colour or form from the non-heated particles.