Comparison of LDPE, LLDPE and HDPE as matrices for phase change materials based on a soft Fischer-Tropsch paraffin wax

Phase change materials based on LDPE, LLDPE and HDPE blended with soft paraffin wax were studied in this work. The purpose of this study was to compare the influence of wax content on the thermal and tensile properties of PE/wax blends. It was found that the different polyethylene/wax blends were immiscible for the samples containing 30-50% wax. The presence of wax influenced the melting and crystallization behaviour of the different polyethylenes in different ways, and the thermal analysis results show that the waxes were evenly distributed in the polymer matrices and that there was no wax leaking during sample preparation. For all the blends the thermal stability decreased with an increase in wax content, and the PE/wax blends degraded in two clearly distinguishable steps. The presence of wax generally caused a reduction in tensile properties, but the extent of the wax' influence depended upon the morphology of the polyethylene. (C) 2010 Elsevier BM. All rights reserved.