Dielectric Spectroscopy of PP/MWCNT Nanocomposites: Relationship with Crystalline Structure and Injection Molding Condition

In this paper, we study the correlation between the dielectric behavior of polypropylene/multi-walled carbon nanotube (PP/MWCNT) nanocomposites and the morphology with regard to the crystalline structure, nanofiller dispersion and injection molding conditions. As a result, in the range of the percolation threshold the dielectric behavior shifts to a more frequency-independent behavior, as the mold temperature increases. Moreover, the position further from the gate appears as the most conductive. This effect has been associated to a modification of the morphology of the MWCNT clusters induced by both the flow of the molten polymer during the processing phase and the variation of the crystalline structure, which is increasingly constituted by gamma-phase as the mold temperature increases. The obtained results allow one to understand the effect of tuning the processing condition in the frequency-dependent electrical behavior of PP/MWCNT injection-molded nanocomposites, which can be successfully exploited for an advanced process/product design.

Automated summary

This paper investigates the correlation between the dielectric behavior of PP/MWCNT nanocomposites and the morphology with respect to crystalline structure, nanofiller dispersion, and injection molding conditions. The study reveals a shift towards more frequency-independent behavior at the percolation threshold with increasing mold temperature, and the most conductive position is found further away from the gate. These findings highlight the importance of tuning processing conditions for the frequency-dependent electrical behavior of PP/MWCNT injection-molded nanocomposites in advanced process and product design.