Synthesis and characterization of polyimides & co-polyimides derived from diol monomers

Abstract

New aromatic diimide-diol monomers were synthesized from corresponding dianhydride and ethanolamine through nucleophilic substitution reaction. The structures of the monomers were characterized by FT-IR & 1H-NMR analysis. Processable polyimides (PIs) & co-polyimides (co-PIs) were synthesized from these new diol monomers and 4,4′-difluorobenzophenone through nucleophilic displacement polymerization reaction. The PIs & co-PIs were characterized by FT-IR, 1H-NMR, X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC), solution viscosity, solubility test and dielectric property. The PIs & co-PIs showed good solubility due to the presence of flexible linkages. The PIs & co-PIs exhibit good thermal stability, the 10 % weight loss occurred in the range 400–425 °C in N2 atmosphere and the glass transition temperatures were in the range 181–196 °C. The dielectric constants (er) of PIs & co-PIs in the range 3.20–3.90 showed that they have excellent electrical insulation characteristics and such polymers can be used as electrical insulation materials for a system operating at high temperature for a long time.