Structure and mechanical properties of blown films of ionomer-compatibilized LDPE nanocomposites

Blown films based on low density polyethylene (LDPE) organoclay nanocomposites (NCs) were obtained by melt extrusion followed by film blowing, using a zinc ionomer of poly(ethylene-co-methacrylic acid) (Pema-Zn) as a compatibilizer. The parameters studied were the compatibilizer and the montmorillonite (MMT) contents that ranged from 0 to 20% and from 0 to 5%, respectively. The presence of clay hindered Pema-Zn crystallization indicating the existence of interaction between the Pema-Zn and the clay. Analysis of the nanostructure showed that the MMT was found inside microscopic domains of Pema-Zn distributed throughout the LDPE matrix. The addition of Pema-Zn improved the dispersion of the clay in LDPE films resulting in synergistic improvements in the mechanical properties. These improvements occur both in the machine and transverse directions. Thus, the presence of Pema-Zn is a determining factor in biaxiality and can clearly be attributed to the bidimensional laminar structure of clays such as MMT. (C) 2012 Elsevier Ltd. All rights reserved.