The improved thermal oxidative stability of silicone rubber by using iron oxide and carbon nanotubes as thermal resistant additives

To investigate the effects of crystalline forms of iron (III) oxide and the bound between γ-Fe2O3 and carbon nanotubes (CNTs) on the thermal oxidative stability of silicone rubber, a series of silicone rubber based composites filled with CNTs, α-Fe2O3, γ-Fe2O3, a mixture of γ-Fe2O3 and CNTs, and γ-Fe2O3 modified CNTs (γ-Fe2O3 − CNTs) were prepared, respectively. Characterizations of the additives and the composites were performed by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The results indicated that the presence of CNTs affected the crystalline form of attaching Fe2O3 which was changed from α to γ. γ-Fe2O3 also got a enlarged special surface area in the γ-Fe2O3 − CNTs. γ-Fe2O3 was a more effective thermal resistant additive than α-Fe2O3 due to the changes of crystalline form during the thermal aging. A synergy was found in the γ-Fe2O3 − CNTs and much more changes of valence made γ-Fe2O3 − CNTs as a more effective thermal resistant additive.