Thermal Characteristics of Polypropylene Composites Filled with TiO2

Abstract

Particulate filled polymer composites with excellent thermal characteristics are highly demanded in electronic industries. In this context, the present work attempts to modify the thermal properties of Polypropylene (PP) by addition of micro-sized titanium dioxide (TiO2) particles. The values of the effective thermal conductivities (keff) of these composites are also estimated using a theoretical model proposed previously. Finally a series of PP-TiO2 composites with different TiO2 concentrations (0-25 vol%) are prepared by compression molding technique and their thermal conductivity, glass transition temperature (Tg) and coefficient of thermal (CTE) expansion are measured using the Unitherm™ Model 2022 tester and Perkin-Elmer DSC-7 thermal mechanical analyzer (TMA) respectively. The measured effective thermal conductivity values are then compared with the values obtained from the proposed model. It is seen that the keff values obtained from theoretical model are in good agreement with the measured values for composites with TiO2 concentrations up to 15 vol%. This study shows that addition of TiO2 particles improves the effective thermal conductivity of PP-TiO2 composites. With addition of 25 vol% of TiO2, there is an enhancement of about 266% in the keff. Apart from enhancing thermal conductivity, incorporation of TiO2 results in improvement of glass transition temperature and reduction in coefficient of thermal expansion of polypropylene resin.