THERMAL-DEGRADATION CHARACTERISTICS OF NATURAL-RUBBER VULCANIZATES MODIFIED WITH PHOSPHORYLATED CASHEW NUT SHELL LIQUID

The thermal and thermo-oxidative decomposition characteristics of Natu ral Rubber (NR) vulcanizates modified with Phosphorylated Cashew Nut S hell Liquid (PCNSL) have been studied by Thermogravimetric Analysis (T GA), Differential Scanning Calorimetry (DSC) and Differential Thermal Analysis (DTA). The PCNSL modified NR vulcanizate showed improved ther mal stability in air, compared to that in nitrogen, which is presumed to be due to the formation of intermediate thermally stable structures in the former. The kinetic parameters for the initial stage of degrad ation in air and in nitrogen have been evaluated by the Freeman-Carrol l method. The higher value for activation energy for thermo-oxidative degradation of PCNSL modified NR (15.10 kCal/mol) and Integral Procedu ral Decomposition Temperature, IPDT (366 degrees C), as against that f or unmodified NR (13.04 kCal/mol and 347 degrees, respectively) indica te the improved thermal stability of the rubber. (C) 1996 Elsevier Sci ence Limited