CONDENSATION POLYIMIDES FROM AB-TYPE AMINO ANHYDRIDE MONOMERS

Starting from alpha-tetralone and maleic anhydride, novel AB-type amin o anhydrides 3 and 5 were synthesized in good yields and obtained in h igh purity without self-condensation. The tetrahydro[5]helicene monome r 3 could be readily polymerized in m-cresol to give polyimide 8 with high molecular weight. Although direct polymerization of the [5]helice ne monomer 5 afforded only an insoluble oligomer, the high molecular w eight [5]helicene-based polyimide 9 could be readily obtained as powde rs and thin films from the precursor polyimide 8 upon treatment with b romine at elevated temperatures. Young's moduli of thin films as asses sed by TMA for polyimides 8 and 9 were 2.91 and 6.34 GPa at 25 degrees C, respectively. Random and regularly alternating copolymers of the A B monomer 5, m-phenylenediamine, and 4,4'-(hexafluoroisopropylidene)di phthalic anhydride were made and showed improved solubility over the h omopolymer 9.