Rheological behavior of poly(propylene) reinforced with graphene nanoplatelets for injection molding

Abstract

Poly(propylene) (PP)-based graphene nanoplatelets (GnPs) nanocomposites are processed by a melt blending technique. To obtain more knowledge about the rheological behavior of nanocomposites for injection molding, the rheological characterization of nanocomposites is performed using a double capillary rheometer over a shear rate range from 10 to 6000 s^-1. The influence of processing temperature (170, 180, and 190ºC) is evaluated. To improve the interaction between PP and GnPs, maleic anhydride (MA) is applied as a compatibilizer. The viscosity master curves are fitted to the Cross-WLF model. In relation to neat PP, the presence of GnPs promote a viscosity decrease. The nanocomposites containing MA exhibit a higher viscosity than the noncompatibilized counterparts, suggesting adhesion improvement between PP and GnPs. In addition to the MA compatibilizer effect, the results show that its presence could act as a plasticizer/lubricant in the PP matrix. The morphology characterization of nanocomposites suggests that in addition to improving the adhesion between PP and GnPs, the MA presence also improved the GnPs dispersion in the PP matrix. The presence of GnPs and MA can affect the Newtonian behavior of the PP matrix. All studied samples reveal thermo-rheological simplicity and pseudo-plastic behavior.