Preparation of dopamine-functionalized multi-wall carbon nanotube/poly(amide-imide) composites and their thermal and mechanical properties

Covalent functionalization of MWCNT-COOH with dopamine was conducted by microwave irradiation and the dopamine-functionalized MWCNTs (MWCNT-Dop) were used as fillers in poly(amide-imide) (PAI) to improve its thermal and mechanical properties. Results indicate that the MWCNT-Dop is dispersed in PAI very well, which is ascribed to a good interfacial interaction between the MWCNT-Dop and PAI by hydrogen bonding. The temperatures at which 10 wt% weight loss occurs, and the limiting oxygen indices increase from 398 to 483 oC and 35.5% to 41.5%, respectively, as the MWCNT-Dop content increases from 0 to 15 wt%. The tensile strength and Young's modulus also increase from 79.4 to 120.3 MPa and 2.0 to 3.3 GPa, respectively, as the MWCNT-Dop content increases from 0 to 15 wt%.