Valorization of plastic waste from polymerization process of styrenic resins

MARCOS VOLPIN; YAMILA V. VAZQUEZ; SILVIA E. BARBOSA

Ciudad Autónoma de Buenos Aires (CABA)

Congreso; 11th WORLD CONGRESS OF CHEMICAL ENGINEERING; 2023

Asociación Argentina de Ingenieros Químicos

The amount of plastic waste generated by the global population has increased continuously throughout history, with the quality varying according to socioeconomic changes, mainly by consumption habits. It is estimated that approximately 350 million tons/year of plastic waste are generated from various sources and stages of the plastic life cycle. These stages are divided into three categories: plastic resin production, product manufacturing, and post-consumer materials. Concerning the production stage of plastic resins, waste generated during styrene-butadiene rubber (WSBR) polymerization is of particular interest, because the constant and continuous increasing demand for this type of polymer from the automotive industry growth involves the generation of production wastes. On the other hand, plastics from Waste Electrical and Electronic Equipment (WEEE), is another waste stream of great interest related to the post-consumer stage in the plastic life cycle, due to its exponential growth in recent years and the challenge that recycling implies. This waste stream is mainly composed of thermoplastics like high-impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS), which can be easily recycled by reprocessing [1]. The aim of this work is to develop sustainable methodologies for the valorization of WSBR, reinserting them in the life cycle of plastics and, as a result, promoting their recycling in order to reduce the generation and final disposal of plastic waste while taking into account Circular Economy concepts. Two strategies to achieve this goal are proposed: a) direct mixing of WSBR with plastics from WEEE, HIPS, and ABS; and b) WSBR as a compatibilizer for HIPS/ABS blends from WEEE. Blends of each plastic WEEE with 20 wt% WSBR are analyzed for the first strategy. In the second one, two different proportions of mixed HIPS/ABS are studied, one with 80 wt% of ABS (H20/A80) and the other with 80 wt% of HIPS (H80/A20), in both proportions 20 wt% of WSBR was added. Mechanical properties of all blends comparatively presented in Figure 1 show that blending WSBR with mixed plastic WEEE is the most sustainable strategy for WSBR valorization because it admits higher amounts of WSBR, resulting in materials with better mechanical properties while avoiding the sorting step of plastic WEEE. Consequently, the overall process is simpler and less expensive.