Fig. 2b shows that the weight loss rate reached its highest values
between 270 and 480 C. The adding of sawdust reduced the
maximum weight loss temperatures. A relatively smaller weight
loss was observed when the pyrolysis of rubber with adding sawdust
performed in the temperature range of 670–760 C comparing
to the other temperature ranges, as shown in Fig. 2b. That reduction
was probably because: (1) it was easier to produce small
molecular gaseous CO2 at higher pyrolysis temperatures. (2) The
thermal decomposition of rubber was basically completed at temperature
range of 670–760 C and the oxygen had more opportunities
to participate in the formation of gases, such as CO2.
The rubber presented two distinct stages of weight loss as
shown in Fig. 2b (Williams and Besler, 1995). One was the main
decomposition stage for releasing vapors; the other was the
removal of the small molecule gases (CO, CO2, and SO2) due to
the higher temperatures. Fig. 2b shows that the adding of sawdust
increased the rate of weight loss at a lower temperature. The
higher the sawdust content in the rubber, the higher the rates of
weight loss were obtained. It was revealed that the adding of sawdust
accelerated the vapor release in the samples, resulting in a
reduced residual carbon. A similar trend and nonlinear relationship
between the amount of sawdust added and the gas yield were also
found by Jin et al. (2012).