Polypropylene assisted phase separation nylon-6 antistatic composites: MWCNTs-NH2 and CB-NH2 as hybrid conductive nanofillers

Abstract

Antistatic nylon-6 (PA6) composites have attracted considerable attention due to their tailored properties for electronics, textiles, and automotive applications. In this paper, the antistatic PA6 composites comprising with polypropylene (PP), aminated multi-walled carbon nanotubes (MWCNTs-NH₂) and aminated carbon black (CB–NH₂) were prepared by melt blending and compression molding. In the composite system, PP was used as the co-matrix to assist the phase separation of PA6. MWCNTs-NH₂ and CB-NH₂ were introduced as conductive fillers. All composites showed good thermal stability with the T_{5 %} higher than 376 °C and the composites containing fillers showed higher residues after thermal degradation due to the good thermal stability of MWCNTs-NH₂ and CB-NH₂. The DSC and XRD results indicated that the crystallization properties of the composite materials were determined by PA6 and PP rather the conductive fillers. In general, the introduction of conductive fillers decreased the mechanical properties but effectively improved the conductivity of the composites and then the antistatic properties. Besides, the antistatic analysis and mechanical test denoted that MWCNTs-NH₂ and CB-NH₂ showed synergistic effect on improving the antistatic and mechanical properties of the composites, which was more evident at high MWCNTs-NH₂ quantity. The micromorphologies obtained by SEM first confirmed the ductile fracture of these composites, and then disclosed a two-phase structure of PA6 and PP polymer matrix, where the conductive fillers were found in the PA6 phase. Considering both mechanical and antistatic properties, the composite (PCNB-3) containing both 3 phr MWCNTs-NH₂ and CB-NH₂ was proposed for the antistatic PA6 composite.