Water as Solvent in Polyimide Synthesis II: Processable Aromatic Polyimides

Some representative thermal, chemical and mechanical characteristics of ‘commercial type’ polyimides are presented in this second paper in a series on using water as solvent in polyimide synthesis. The commercial types of polyimide that have been produced in this study are closely related to Kapton, Upilex R®, Upilex S®, Avimid N® and PMR-15. The chemical characterization of these materials using both nuclear magnetic resonance and Fourier Transform infrared indicate very pure and fully imidized products. The thermal and mechanical data from techniques such as thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical thermal analysis reveal properties that are at least, equivalent to their commercial counterparts. Some improvement in processability is noted in pure materials, mixtures and chemically modified analogues of these well known polyimides. In addition this highly efficient one-pot method potentially provides economic advantages through low solvent cost and environmental impact benefits.