New Polyisoimides: An Approach to In Situ Rigid-Rod Polyimide Formation

摘要

In situ generation of rigid rod polymides was investigated by synthesizing a series of soluble (DMAC) benzidine and p-aminobenzene derivative based polyisoimides. The synthesis was carried out by reacting equimolar amounts of new and commercial diamines with pyro-mellitic dianhydride and then cyclodehydrating the resulting polyamic acids with DCC to give polyisoimides. The newly prepared polymers had I.V.'s ranging from 0.25 to 1.89. Neat and composite films of the polyisoimides were cast from DMAC and isomerized with heating to produce the rigid rod polyimides. The resulting cured films showed no visible signs of phase separation. A study of the isomerization reaction (polyisoimide to polyimide) was conducted by FTIR.