Evaluation of the properties onbinary blendsof post-consumer mixed polymers with recycled polypropylene

Abstract

Polyolefins make up a large proportion of the great post-consumer polymer stream. Due to their similar chemical and physical properties, it is difficult to collect and sort them separately, so it is common for them to be mixed during recycling processes, which is why they are called mixed recycled polyolefins. For this reason, it is important to obtain information about their thermal, rheological and mechanical behavior and to study how these properties vary in their blends, which will serve to predict their subsequent performance and their technical standardization, facilitating the recycling process. Thus, the objective of this work is to study the properties of binary blends ofrecycled polypropylene withrecycled mixed polyolefins, specifically high density polyethylene and low density polyethylene recycled in different proportions, without using compatibilising agents. In addition, blends of recycled polypropylene with recycled polylactic acid are studied as an alternative for 3D printing waste, a prevalentprocessing method for this polymer. Binary blends were made at 20, 40, 60 and 80% by weight using a twin-screw extruder and the properties of each blend were determined by infrared spectroscopy, differential scanning calorimetry, melt flow index measurements and tensile tests. The results revealed that although there was no miscibility, the polyethylene blends gradually increasedtensile strength with the addition of recycled polypropylene.