Use of postconsumer polyethylene in blends with polyamide 6: Effects of the extrusion method and the compatibilizer

Blends of polyamide and high-density polyethylene show adequate properties for a large range of applications: they are used for the production of filaments, containers, and molding resins. The effect of the addition of 2 wt % of a compatibilizer, maleic anhydride grafted polyethylene, to the blend was studied and compared to the use of postconsumer polyethylene. The samples were extruded with single- and twin-screw extruders with 25,50, or 75 wt % f polyethylene, and the test specimens, molded by injection, were characterized by stress-strain tests, thermal properties, and morphologies. Processing the blends with postconsumer polyethylene in both extruders improved the mechanical properties in comparison to the blends processed with high-density polyethylene and the compatibilizer. The morphologies of these blends showed that there was a decrease in the domain size of the disperse phase with the use of the compatibilizer or postconsumer polyethylene. The results indicate that for this blend, postconsumer polyethylene substituted, with advantages, for the necessity of a compatibilizer and the use of the high-density polyethylene. (C) 2008 Wiley Periodicals, Inc.11031310131