Study of selected thermal characteristics of polypropylene/polyethylene binary blends using DSC and TGA

The characteristics of polypropylene/polyethylene (PP/PE) binary, blends at the microscopic level have been widely studied by different researchers over the years. This Communication discusses the empirical results obtained from a series of DSC and TGA tests on the selected thermal properties of PP/PE blends. Using DSC in our investigation is aimed at revealing the effects of different blending ratios of PP and PE on the melting and crystallinity behaviour of the blend systems, while the application of TGA is to study the degradation characteristics of the blends in terms of their induction time. An empirical equation is proposed and has been proved to offer a convenient means for the estimation of the overall crystallinity percent of a PP/PE system. It largely requires the knowledge of blend ratios and the densities of the pure components, and eliminates the tedious graphical integration process on determining areas under curves of thermograms. The TGA study shows that the effect of temperature on induction time of PP/PE blends follows the trend of the Arrhenius equation. (C) 2002 Elsevier Science Ltd. All rights reserved.