Preparation and Performances of Polyimide-Insitu formed Polydiphenylsiloxane Nano hybrids

Abstract

Polyimide-polydiphenylsiloxane (PI-PDPS) hybrid films were synthesized by blending poly(amide acid)(PAA) and diethoxydipheylsilane(DEDPS). PAA was prepared from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride (BPDA), p-phenylenediamine (PDA), and PDPS was formed from DEDPS into PAA by in-situ polymerization through sol–gel process. The weight ratio of PDPS, applied in PAA, was 5, 10, 20 and 50%. 1H NMR and IR confirmed the sol–gel reaction and imidization. The molecular weight of PDPS was measured by Size exclusion chromatography (SEC). Presence of inorganics, their size and distribution in the hybrid were investigated by scanning electron microscopy (SEM). The transparency of the hybrids were evaluated from UV–vis spectra. Interestingly, the transparency was increased in presence of only 5% PDPS in PI. Also the crystal effect of PDPS was found in PI in presence of 20 and 50% PDPS prominently which revealed by XRD. PI-5 %PDPS hybrid provides higher tensile modulus, glass transition temperature, degradation temperatures, char yield in compare to PI.