Blends with technological potential of copolymer polypropylene with polypropylene from post-consumer industrial containers

Abstract

Polypropylene is one of the most consumed thermoplastics in the transformation industry, generating a large volume of post-consumer waste. The practice of reusing materials presents an opportunity for the revaluation of post-consumer plastic waste, aiming to minimize the negative impacts of its disposal. In this work, blends of copolymer polypropylene (PPCop) and recycled copolymer polypropylene (PPRec) from industrial containers were evaluated using 20, 40 and 60% of PPRec. The blends were initially prepared in a co-rotational twin screw extruder, and thereafter, the extruded granules were injection molded. The mechanical, thermal, thermomechanical properties and morphology of the blends produced were evaluated. There was an increase in elastic modulus, tensile strength, heat deflection temperature (HDT), Vicat softening temperature and thermal stability, as compared to the PPCop matrix. An increase in crystallinity was observed by Differential Exploration Calorimetry (DSC), being favored by the reduction of the blends viscosity as verified in the melt flow index (MFI). However, losses were seen in impact strength and elongation at break. The morphologies obtained with the Scanning Electronic Microscope (SEM) are typical of immiscible blends, with spherical domains dispersed in a continuous matrix. The results indicate that PPCop/PPRec blends can contain up to 60% of recycled material by weight, while maintaining quality and reducing the product final cost.