Pyrolysis Polybutadiene Model Including Self-Heating and Self-Cooling Effects: Kinetic Study via Particle Swarm Optimization

Thermogravimetric analyses of polybutadiene rubber was carried out under heating rates ranging up to 50 K min−1. A kinetic model, consisting of two parallel reactions is used. The kinetic parameters are estimated using particle swarm optimization method. Independently to the heating rates, the kinetic parameters are respectively 1.24 and 1.18 for reaction orders, 7.15 × 1012 and 8.61 × 1015 s−1 for pre-exponential factors and 182 and 249 kJ mol−1 for activation energies. The dependency of the thermal behaviour to the heating rates is caused by the self-heating and self-cooling effects. Increasing heating rate from 1 to 50 K min−1 causes the increase of the first individual weight fraction, which degrades exothermically, from 8 to 43 wt% at the expense of the second, which degrades endothermically. The generated self-heating raises the sample temperature up to 25 °C above that of the oven.