Effects And Mechanism Of Silica Nanotubes Coated Carbon Nanotubes On Thermal Oxidative Stability Of Silicone Rubber

Silicone rubber(SR)is a kind of high performance rubber.One of the most remarkable properties is thermal resistance.Although its thermal stability is already considerably high,with the rapid development of science and technology,there is an increasing demand for better thermal resistant SR in modern times.It has been verified that carbon nanotubes(CNTs)with special structure and excellent performance can be used as an additive to improve the thermal oxidative stability of silicone rubber.In this paper,CNTs werecoated by silica nanotubes(SNTs)to produce SNTs@CNTs particles through sol-gel method.Then SNTs@CNTs was blended with SR to fabricate SNTs@CNTs/SR composites.TEM(including EDS),FTIR and TG were performed to demonstrate the coating states of SNTs on the surface of CNTs.SEM showed the dispersion of CNTs in the matrix.Raman spectra were performed to detect the interfacial interaction between nanoparticles and SR matrix.Furthermore,mechanical properties before and after thermal aging of composites and their TG have been analyzed,in order to characterize the thermal oxidative stability of SR based nanocomposites and select the optimum SNTs@CNTs/SR sample with the best thermal oxidative stability.After that,thermal conductivity,swelling and TG-FTIR testing were employed to further investigate the action mechanism of SNTs@CNTs during the thermal oxidative degradation process of SR.The results indicated that SNTs was coated onCNTs.SNTs@CNTs effectively restrained the aggregation of CNTs in the matrix,and significantly improved the interfacial interaction between CNTs and the matrix.The thermal oxidative stability of SR nanocomposites was improved.The thermal conductivity and TG-FTIR testing revealed that after the incorporation of SNTs@CNTs,the thermal conductivity of silicone rubber was notably increased.The increasing rate is up to 48%.The whole thermal degradation process of SR moved to higher temperature,especially the initial thermal degradation temperature of the degradation products is 41 °C higher than that of silicone rubber.And meanwhile,the thermal degradation of silicone rubber to cyclic oligomers was hindered.