Effect of shear rate and pressure on the crystallization of PP nanocomposites and PP/PET polymer blend nanocomposites

The effect of shear flow on the crystallization of homopolymers has been widely studied, however more complex systems such as nanocomposites or polymer blends nanocomposites (PBNANOs) have received less attention. In this work, the effect of pressure and shear flow on the crystallization process of polypropylene-based nanocomposites and polypropylene/polyethylene terephthalate PBNANOs have been studied employing dilatometry (PVT), X-ray, rheology, and DSC. The material systems used allow studying the effect of shear in the presence of nanoparticles that do not have a nucleating effect, as well as the combined effect of shear and nucleating nanoparticles. Nucleating nanoparticles increase the crystallization temperature more significantly because of the combined effect of nucleation and flow. For carbon nanotubes, nucleation is more pronounced due to stronger interactions with PP chains, as demonstrated by rheological measurements. For PBNANOs the effect of shear on crystallization is more significant due to the higher amount of available surfaces.