Optimization of thermal and rheological properties of HDPE-organoclay composite using response surface methodology

Abstract

The processing parameters to disperse active filler within a polymer matrix to enhance the polymers’ properties should be selected carefully to achieve the best dispersion. In this research, Box-Behnken Design (BBD), an experimental design for response surface methodology (RSM), with three levels was used as a design of experiment (DOE) to analyze the effect of processing parameters on the thermal and rheological properties of high-density polyethylene-organoclay (HDPE-OC) composites prepared by adding organoclay (OC) to high density polyethylene (HDPE) using melt blending method. HDPE-OC composites were characterized morphologically by SEM and XRD, and thermally by DSC and TGA, and tested rheologically. Investigated factors were filler amount, mixing temperature and screw speed. The evaluated responses were melting temperature, degradation temperature, storage modulus, and complex viscosity of HDPE-OC composites. The effect of each factor on the responses was determined through an analysis of variance (ANOVA). The obtained data was used to predict the responses by fitting into a second order equation with MINITAB software. Constructed models were verified using validation experiments therefore optimum melt blending processing parameters obtained as 1.5 wt.% of OC, mixing temperature of 183 °C, and screw speed of 77 rpm for HDPE-OC composites.