Preparation, morphology and properties of acid and amine modified multiwalled carbon nanotube/polylmide composite

The precursor of polyimide, polyamic acid, was prepared by reacting 4,4'-oxydianiline (ODA) with 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA). Unmodified, acid-modified and amine-modified multiwall carbon nanotubes (MWCNT) were separately added to the polyamic acid and heated to 300 degrees C to produce polyimide/carbon nanotube composite. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) microphotographs reveal that acid-modified MWCNT and amine-modified MWCNT were dispersed uniformly in the polyimide matrix. The effect of the acid and amine-modified MWCNTs on the surface and volume electrical resistivities of MWCNT/polyimide composites were investigated. The surface electrical resistivity of the nanocomposites decreased from 1.28 x 10(15) Omega/cm(2) (neat polyimide) to 7.59 x 10(6) Omega/cm(2) (6.98 wt% unmodified MWCNT content). Adding MWCNTs influenced the glass transition temperatures of the nanocomposites. Modified MWCNTs significance enhanced the mechanical properties of the nanocomposites. The tensile strength of the MWCNT/polyimide composite was increased from 102 MPa (neat polyimide) 134 MPa (6.98 wt% acid modified MWCNT/polyimide composites). (c) 2006 Elsevier Ltd. All rights reserved.