Preparation of polyimide/MWCNT nanocomposites via solid state shearing pulverization (S3P) processing

Polyimide/multiwall carbon nanotube (PI/MWCNT) nanocomposite films with homogeneous MWCNTs dispersion were prepared via a solid state shearing pulverization (S³ P) approach. Polyimide precursor, viz., poly(amic acid) (PAA), was synthesized from 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA). Then, 3,3 ′ ,4,4 ′ -benzophenonetetracarboxylic dianhydride (BTDA) was mixed with the PAA powder and acid functionalized MWCNTs (acid-MWCNTs) by solid state shearing pulverization (S³ P) approach. Finally, PI/MWCNT nanocomposite films were prepared by thermal imidization at elevated temperatures. Using such an approach not only the MWCNTs are welldispersed but also the mechanical and thermal properties of PI are improved. The tensile strength of PI was enhanced by 74% and the elongation at break decreased to 10.35% with 5.0 wt% acid-MWCNT loading. And the glass transition temperature of PI was increased to 341 °C from 303 ° C because of the strong interfacial bonding between PI and acid-MWCNTs. The solid state shearing pulverization ( S ³ P) approach developed in this study provides a novel method to prepare various polymer composites with desired particle dispersion.