Condensation Polyimides from AB-Type Amino Anhydride Monomers

Abstract

Starting from α-tetralone and maleic anhydride, novel AB-type amino anhydrides 3 and 5 were synthesized in good yields and obtained in high purity without self-condensation. The tetrahydro[5]helicene monomer 3 could be readily polymerized in m-cresol to give polyimide 8 with high molecular weight. Although direct polymerization of the [5]helicene monomer 5 afforded only an insoluble oligomer, the high molecular weight [5]helicene-based polyimide 9 could be readily obtained as powders and thin films from the precursor polyimide 8 upon treatment with bromine at elevated temperatures. Young's moduli of thin films as assessed by TMA for polyimides 8 and 9 were 2.91 and 6.34 GPa at 25 °C, respectively. Random and regularly alternating copolymers of the AB monomer 5, m-phenylenediamine, and 4,4‘-(hexafluoroisopropylidene)diphthalic anhydride were made and showed improved solubility over the homopolymer 9.