Thermal property and thermodynamic parameter of rubber blends containing the cyclic structure

Natural rubber (NR) and cyclized NR (90 % cyclization) were blended by dynamic vulcanization using a sulfur curing systems. The rate of vulcanization was slower in rubber blends containing cyclized NR was slower than the one of pure NR. Activation energies have been determined and the order of the thermal oxidative stability evaluated. It was seen that the activation energy of NR phase and the cyclized NR phase was 330-357 kJ/mole and 810-905 kJ/mole, respectively. Moreover, the enthalpy of activation of all sample (with or without cyclized NR) decreased with increasing of frequency.