Thermogravimetric Analysis of Natural Rubber/Silica Nanocomposites

摘要

The thermal degradation process of natural rubber/silica nanocomposites ( sample B ) and natural rubber ( sample A ) at different heating rates in nitrogen was studied by thermogravimetric analysis. The results indicate that the thermal degradation of two samples in nitrogen is a one-step reaction. All the TG and DTG curves shift toward high temperatures with the rising of the heating rate. The degradation temperatures increase linearly with the increasing of the heating rate. The equilibrium thermal degradation temperatures of two samples are as follows, Sample A：T0 0= 350.7℃，TP 0 = 382.4℃ and Tf 0= 412.0℃. Sample B：T0 0 = 358.6℃，TP 0 = 387.3℃ and Tf 0= 418.3℃. It showes that both the thermal degradation temperatures and the equilibrium thermal degradation temperatures of the sample B is higher than sample A evidently. The degradation kinetic parameters such as activation energy ( E ) and frequency factor ( A ) were calculated by Ozawa-Flynn-Wall method. The results show that E and A of two samples vary with the increase degree of decomposition, and the variation trends are similar. According to the variation law of E and A，the degradation process can be divided into four phases：0% - 20%, 20% - 75%, 75% - 90% and 90% - 95%. E increases with increasing degree of decomposition and reaches the maxium when the weightlessness rate is 80%, then the E decreases. During the whole decomposition process，E and A of sample B is higher than sample A evidently. Base on the results above，the thermal stability of sample B can be improved effectively with the SiO2 nanoparticles dispersed in NR matrix.