Desenvolvimento de compósitos de polipropileno com embalagens flexíveis recicladas moldados por injeção

Abstract

This dissertation investigates the addition of recycled multilayer flexible packaging into a polypropylene copolymer matrix as a crucial aspect of developing a composite. The main objective was to reuse this waste, minimizing environmental impacts and optimizing the availability of recycled raw material. To achieve these goals, a methodology was adopted that involved adding different percentages of this waste through mechanical recycling and incorporation by extrusion, followed by injection molding. The study was divided into two stages, with the first stage involving the incorporation of 20%, 30%, 40%, 50%, and 60% of the multilayer flexible packaging waste into the polymer matrix. The mechanical tests showed that the higher the waste percentage in the composite, the stiffer and less impact-resistant it became, while density increased and melt flow index decreased. SEM/EDS revealed that the surface became quite heterogeneous and embedded. The TGA analysis showed an increase in the degree of degradation and residual ash content, indicating the presence of inorganic contaminants in the waste. DSC demonstrated a reduction in crystallinity as the amount of waste increased. In the second stage, the waste percentage was fixed at 50%, due to the balance of properties and to maximize environmental impact. In these composites, 2.5%, 5%, and 10% of Polybond 3200 coupling agent were added via extrusion followed by injection molding. The same analyses from the first stage were performed, and some showed optimized results. The melt flow index increased, while the density remained stable. Crystallinity increased again as the concentration of Polybond 3200 was raised. However, with the addition of 2.5% coupling agent, there was a 42.50% increase in flexural strength, while the samples with 5% and 10% showed increases of 33% and 34%, respectively. [resumo fornecido pelo autor]