Thermal conductivity of PP/Al(OH)3/Mg(OH)2 composites

Polypropylene (PP) composites filled with aluminum hydroxide (Al(OH)(3)) and magnesium hydroxide (Mg(OH)(2)) were prepared using a twin-screw extruder. The effective thermal conductivity (k(eff)) of the composites was measured by means of a thermal conductivity instrument under different testing temperatures. The results showed that the values of k(eff) increased quickly with an increase the volume fraction (phi(f)) of Al(OH)(3)/Mg(OH)(2) powder when phi(f) was less than 7.1%, then k(eff) increased slightly as phi(f) was varying from 7.1% to 13.3%, while the values of k(eff) increased obviously when phi(f) was more than 13.3%. Under the same conditions, the values of k(eff) increased nonlinearly with increasing the diameter (d) of the Al(OH)(3)/Mg(OH)(2) powder. The values of k(eff) of the composites increased somewhat with a rise of test temperature. On the basis of the experimental results, the thermal conduction mechanisms of the composite were analyzed and discussed. (C) 2012 Elsevier Ltd. All rights reserved.