Electro Conductivities of Well-Dispersed PMMA-g-MWNTs/6FDA-Based Polyimide Composites: Effect of Chemical Structure

Abstract

PMMA (polymethylmethacrylate), which is miscible with hexafluoropropane dianhydride (6FDA)-based polyimide, was grafted onto MWNTs surfaces to enhance their dispersion relative to that of pristine MWNTs. The electrical conductivity of the 6FDA-based composite revealed percolation threshold behavior, and the 6FDA-4,4'-(hexafluoroisopropylidene)diamine, (6FpDA):3,5-diaminobenzoic acid (DABA)/PMMA-g-MWNT composite showed a higher percolation threshold concentration and a slightly lower critical exponent compared with those of the 6FDA-6FpDA composite. Because of the weak interaction energies between 6FDA-6FpDA:DABA and PMMA, agglomerated domains were formed. Also, the weak interaction energies of the 6FDA-6FpDA:DABA led to a larger reduction in the normalized transmittance compared with that seen in the 6FDA-6FpDA composite. POLYM. COMPOS., 32:368-377, 2011. (C) 2011 Society of Plastics Engineers