Influência do tipo de polietileno e de compatibilizantes no desempenho de blendas de poliamida 6/polietileno.

Abstract

In this work, the influence of the polyethylene type and compatibilizers in the performance of Polyamide 6 (PA6)/Polyethylene (PE) blends was investigated. Two types of polyethylene were used: Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). The compatibilizers used were: Polyethylene grafted with acrylic acid (PEgAA), Polyethylene grafted with maleic anhydride (PEgMA) and Ethylene – Methyl Acrylate – Glycidyl Methacrylate (EMA – GMA) terpolymer. The blends were prepared by two mixing sequences: In the first one, after being dry-mixed, the blends were injection molded. In the second one, after being dry-mixed, the blends were extruded and then injection molded. The composition of the blends was 80/20 (wt%) for PA6/PE blends and 80/10/10 (wt%) for PA6/Compatibilizer/PE blends. Prior to each process, PA6, PEgAA, and PEgAA were dried under vacuum at 80°C for 24 hours. The blends were characterized through Torque Rheometry, Mechanical Properties, and Scanning Electron Microscopy (SEM). Torque rheometry analysis showed that the addition of compatibilizers to PA6/PE blends has increased the torque. This increase was more pronounced for the blends containing LDPE as disperse phase. Increasing the amount of compatibilizers, the torque of compatibilized blends also increases. PEgAA was more reactive with PA6 than other compatibilizers. However torque decrease was observed due to degradation. Mechanical properties results showed that there is a considerable increase in the impact strength of PA6/LDPE blends when the compatibilizers are added. This increase was more pronounced for the blends containing LDPE as disperse phase. The impact strength of the PA6/PEgAA/PE and PA6/EMA-GMA/PE prepared by extrusion followed by injection was greater than that of the same blends prepared only by injection. The impact strength of PA6/PEgMA/PE blend prepared by injection was greater v than that of the same blends prepared by extrusion followed by injection. SEM analysis showed that the addition of compatibilizers to PA6/PE blends has greatly decreased the PE particles average size and improved the adhesion between PA6 and PE phases, increasing the impact strength.