PARTIAL PHASE-DIAGRAMS OF POLY(P-PHENYLENE TEREPHTHALAMIDE) COPOLYMERS IN SULFURIC-ACID

Copolyaramides with 2,5-di-n-hexyl terephthalic acid residues as comon omers were synthesized. Partial phase diagrams were measured for mixtu res with concentrated sulfuric acid in the range between 8 and 20% w/w of polymer. Lyotropic phases were observed, but in comparison to homo poly(p-phenylene terephthalamide) the clearing temperatures are lower and the critical concentrations for the formation of the lyotropic nem atic phase are increased. The existence of a master curve for the clea ring temperature as it depends on the concentration of the components of both homo- and copolymers illustrates that the side chains act main ly as an 'attached solvent' to the rigid main chains.