Tracking the progression of dispersion of graphite nanoplates in a polypropylene matrix by melt mixing

Abstract

This work reports the dispersion of graphite nanoplates (GnP) in polypropylene by melt mixing using a small-scale continuous prototype mixer. The focus is to study the progression of the dispersion of GnP, a process that is not well understood. Composites were prepared with 2 and 4 wt% of GnP, as-produced and functionalized by grafting polypropylene modified with maleic anhydride to the GnP surface. The processability of the composites was similar to that of polypropylene, as assessed by capillary rheometry. The nanoparticle dispersion was analyzed by optical microscopy. The progression of the number of agglomerates and their size, for pristine and functionalized nanoparticles, was observed along the mixer. The final agglomerate dimensions were found to be similar for pristine and functionalized GnP, and indicated that agglomerate dispersion progressed toward individual nanoparticles. The interface improvement of functionalized GnP with polypropylene was observed by scanning electron microscopy.