Desenvolvimento de bioblendas de poli (ácido lático)/polietileno compatibilizadas com copolímeros contendo grupos metacrilato de glicidila.

Abstract

In this work, blends of poly(lactic acid) (PLA) with polyethylene (PE) were produced, aiming to toughen the PLA. The polyethylene used was a commercial biopolyethylene obtained from renewable sources. The work was divided into two stages. The experimental part concerning the first stage was conducted at the Federal University of Campina Grande (UFCG), whereas the experimental part concerning the second stage was performed at the Washington State University (WSU) located in the USA, due to the completion of a doctoral internship. In the first stage of the work, blends of poly(lactic acid) and polyethylene, PLA/PE, were compatibilized by different compatibilizing agents, the ethylene-glycidyl methacrylate (E-GMA) and the ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA). In the second stage, glycidyl mathacrylate (GMA) and maleic anhydride (MA) functional groups were grafted onto polyethylene using the conventional method of initiating grafting reactions, i.e., initiation by thermal decomposition of a peroxide, and using a new method of initiation by redox reactions in the molten state. The GMA grafted polyethylene was used for the production of blends with PLA to evaluate the effect of t these reactive groups on the properties of the blend. From the results obtained in the first stage it was observed that both compatibilizers, E-GMA and EMA-GMA, were effective in compatibilizing the blends which led to the toughening of PLA. The results obtained in the second stage showed that the initiation method by redox reactions promoted improvements in the degree of grafting and in grafting efficiency. The grafting of GMA groups onto polyethylene, PE-g-GMA favored the compatibility of the blend PLA/PE which increased with increasing GMA concentration.