Study on thermal degradation of sol and gel of natural rubber

The thermal degradation of natural rubber (NR) in air at a constant heating rate was studied by using of the thermogravimetry (TG) and thermogravimetr y and differential thermal analysis (TG-DTA) simultaneous techniques. It in dicates that the temperature of thermal degradation of gel and sol of NR ri ses linearly along with the increment of the heating rate, whereas the heat ing rate has little effect on the degree of thermal degradation. Accompanyi ng other side reactions, the thermal degradation of NR is not a simple rand om chain scission process, and it is an exothermic reaction. The dynamic va riation of molecular structure of NR during the thermal degradation was stu died using Fourier transform infrared spectroscopy (FTIR). It shows that th e products of the thermal degradation of both sol and gel of NR are hydrope roxide, carbonyl, and hydroxyl compounds. The formation of gel makes the te mperature of the thermal degradation of NR decrease and the rate of the the rmal degradation increase; thus, the thermal stability of NR is reduced. (C ) 2000 John Wiley & Sons, Inc.