Microinjection molding: Influence of molding parameters on the electrical conductivity of polypropylene filled with multi-walled carbon nanotubes

Polypropylene (PP) composite with 10 wt% multi-walled carbon nanotubes (CNT) was prepared by melt dilution and then subjected to microinjection molding (μIM) process. A mold with a three-step configuration along the flow direction was adopted. The influence of actual injection molding parameters on the electrical conductivity of the microparts was evaluated by design of experiments (DOE) method. The distribution of maximum shear rates within the microparts was simulated via Autodesk Moldflow Insight, and the distribution of CNT along the flow direction was examined by scanning electron microscopy (SEM). Results indicated that the distribution of overall maximum shear rates follows an order of thin section>middle section>thick section, in harmony with the state of dispersion of CNT within the micro-components.