Colorless and transparent polyimide nanocomposites: Comparison of the properties of homo- and co-polymers

A series of colorless and transparent polyimide (PI) hybrids were synthesized from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 2,2′-bis(trifluoromethyl)benzidine (TFB) with various organoclay contents, via solution intercalation polymerization to form poly(amic acid)s (PAAs). In addition, copolyimide (Co-PI) hybrids were synthesized from TFB with different ratios of 6FDA and pyromellitic dianhydride in combination with the organoclay. The thermo-optical properties, morphologies, and gas permeations of the Homo-PI and Co-PI hybrid films were examined for organically modified hectorite (STN) loadings ranging from 0 to 40 wt%. The properties of Homo-PI hybrid films were compared with those of films prepared from the Co-PI hybrids.