Microinjection molding of polyoxymethylene/multiwalled carbon nanotubes composites with different matrix viscosities

This study features the effect of matrix viscosity on the properties of carbon nanotubes reinforced polyoxymethylene (POM/CNT) microparts, which were obtained via melt blending and subsequent microinjection molding (mu IM) processes, under a defined set of processing conditions. Results of compression molding and mu IM were compared to assess the influence of processing methods (i.e., thermomechanical history) on the electrical and thermal conductivities, melting and crystallization behavior as well as the thermal degradation resistance of POM/CNT composites. Filler orientation in POM/CNT microparts was evaluated using Raman spectral analysis. The electrical conductivity measurements revealed that matrix viscosity plays a significant role in determining the distribution of CNT. Also, the extreme shearing conditions that prevail in mu IM are unfavorable for the construction of random conductive pathways within the micromoldings, as corroborated by transmission electron microscopy. Although the thermal degradation resistance of both POM/CNT composites and corresponding microparts deteriorated with increasing filler concentration, samples prepared with higher matrix viscosity showed higher thermal stability when compared with lower matrix viscosity counterparts. This study provides valuable insights into fabricating multifunctional microparts for potential industrial applications in replacement of metallic components for precision electronic instruments.

Automated summary

The study reveals that matrix viscosity significantly affects the properties of carbon nanotubes reinforced polyoxymethylene microparts, with samples prepared using higher matrix viscosity showing higher thermal stability. Additionally, the influence of different processing methods on the properties of POM/CNT composites is investigated.