Efeito combinado de copolímeros e da sequência de mistura nas propriedades e na morfologia de blendas com matriz de poli (Ácido lático).

Abstract

Poly (lactic acid) (PLA) is a widely investigated and promising biopolymer, however, it has limitations, such as high brittleness, being necessary to modify its properties. In this work, through blends obtained in a torque rheometer, the reactivity of the polyethylene grafted with acrylic acid (PEgAA) copolymer with the ethylene/acrylate methyl (EMA), ethylene/glycidyl methacrylate (EGMA) and ethylene/methyl acrylate/glycidyl methacrylate (EMA-GMA) copolymers, and the reactivity of EGMA and EMA-GMA with PLA was evaluated. The blends were characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Subsequently, the effect of the combined copolymers and the mixing sequence on the morphology, rheological, mechanical, and thermo-mechanical properties of PLA matrix ternary blends was also studied. The analyzes showed the occurrence of reactions between PEgAA and EGMA and between PEgAA and EMA- GMA. PEgAA was found to be more reactive with EGMA than with EMA-GMA. PEgAA reactivity with EGMA and PEgAA reactivity with EMA-GMA increased with increasing temperature. The mixing sequence affected the rheological properties and morphology of the PLA/EGMA/PEgAA and PLA/EMA-GMA/PEgAA blends. Blends containing EMA-GMA copolymer showed higher impact strength than blends containing EGMA copolymer. In general, relevant information on reactivity between copolymers and mixing sequences has been obtained and can be used for the development of other systems with PLA or other polymeric matrices.