Influence of Surface Modification of Carbon Nanotube on Microstructures and Properties of Polyamide 66/Multiwalled Carbon Nanotube Composites

摘要

The melt-mixing polyamide 66 (PA66) composite samples that incorporated pure, acid- and amine-function-alized multiwalled carbon nanotubes (MWCNTs) were prepared in order to enhance mechanical and frictional properties of PA66 composites. The homogeneous dispersion of amine-functionalized MWCNTs (D-MWCNTs) in PA66 matrix was observed from the significantly uniform morphology of tensile fractured surface of the composites. Differential scanning calorimetry measurement indicates that D-MWCNTs acted as effective nucleation agent for PA66 matrix and the crystallinity of PA66 was increased. The fracture stress and tensile modulus of the composites were significantly improved with the incorporation of D-MWCNTs, owing to the good dispersion of D-MWCNTs. Compared with PA66, the PA66 composites with 1.0 wt% D-MWCNTs were improved considerably in both wear and friction properties owing to the change of the tribological mechanisms. The good dispersion of D-MWCNTs in PA66 and good interface compatibility between D-MWCNTs and PA66 favored the formation of a thin layer on the contact surfaces during wear and friction test, which played an important role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results prove the importance of D-MWCNTs in a positive change of the mechanical and frictional properties of PA66 composites and suggest the applicability prospect of PA66/D-MWCNTs composites in engineering components.