The morphology, crystallization and conductive performance of a polyoxymethylene/carbon nanotube nanocomposite prepared under microinjection molding conditions

This paper comparatively investigated the structures of a microinjection molded part (micropart) and a conventional injection molded part (macropart) of a polyoxymethylene/carbon nanotube (POM/CNT) conductive nanocomposite. We also investigated the influence of microinjection molding conditions on the CNTs dispersion morphology, POM crystallization and conductive properties of the micropart. Results show that the incorporated CNTs improve the replication quality of the prepared micropart. The CNTs morphology and POM crystallization of the micropart are very different from those of the macropart. The POM spherulite structures are formed in the macropart and highly oriented shish-kebab-like structures are formed in the micropart. Differences in the crystallization structures are correspondingly reflected in differential scanning calorimetry (DSC) results. Incorporation of CNTs, an increase in injection rate or a rise in mold temperature are equally conducive to formation of the shish-kebab structures. In addition, an increase of mold temperature and the annealing treatment are both helpful in increasing the conductivity of the micropart.