Properties of polyphenylene sulfide/multiwalled carbon nanotubes composites: a comparison between compression molding and microinjection molding

This work comparatively studied the electrical, morphological, and thermal properties of polyphenylene sulfide/multiwalled carbon nanotubes (PPS/CNT) composites prepared by compression molding (CM) and microinjection molding (mu IM), respectively. The subsequent samples were termed as CM composites and microparts, respectively. Results revealed that the electrical conductivity of PPS/CNT microparts was lower than that of CM PPS/CNT composites, which was ascribed to the difference in shearing which affected microstructural evolution. In addition, SEM observations revealed that the distribution of CNTs became better in the PPS/CNT microparts, which was related to the prevailing higher shearing effect in mu IM. The tensile strength of PPS/CNT microparts dropped for filler concentrations <= 2wt% and it started to increase after reaching 10wt%; in comparison with the PPS/CNT microparts, the tensile strength of CM PPS/CNT samples exhibited an opposite trend when the filler concentration was <= 3wt%. After that, the tensile strength showed a monotonic increase with increasing CNT concentration. Both the uniform distribution of CNT and increase of crystallinity were crucial to improving the tensile strength of PPS/CNT moldings. This work showed that PPS/CNT moldings with good electrical conductivity and mechanical performance can be molded at relatively high filler concentrations, which is critical for applications in demanding engineering sectors.