Effect of Maleated Polyethylene on the Crystallization Behavior of LLDPE/Clay Nanocomposites

Abstract

The crystallization behavior and microstructure of linear low density polyethylene (LLDPE)/modified montmorillonite (20A) composites containing maleic anhydride grafted polyethylene (MA-g-PE) were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscope (TEM). The dispersion of 20A in LLDPE matrix depended on the amount of MA-g-PE. The degree of super cooling reduced when 20A was introduced into LLDPE with MA-g-PE. The Avrami analysis shows that the nonisothermal crystallization process of the LLDPE/20A composites followed the Avrami equation with Avrami exponent value in the range of 2.75–3.97. The activation energies calculated by Kissinger method were 986 kJ/mol for LLDPE, 949 kJ/mol for PE-A5MA0, 1445 kJ/mol for PE-A5MA5, and 1581 kJ/mol for PE-A5MA20. The activity of nucleation of PE-A5MA0 was 0.75 but the values of the composites with MA-g-PE were in the range of 0.37–0.56. These behaviors can be interpreted by the fact that the loading of MA-g-PE in LLDPE/20A composites enhances the dispersion of clay in LLDPE matrix and the good dispersion of 20A affects the degree of super cooling and the nucleation activity of silicate.