Effect and mechanism of iron oxide modified carbon nanotubes on thermal oxidative stability of silicone rubber

To investigate the effects of iron (III) oxide attached on carbon nanotubes (CNTs) surface on the thermal oxidative stability of silicone rubber (SR), a series of iron oxide modified carbon nanotubes (γ-Fe2O3–CNTs) with different sizes or loadings of γ-Fe2O3 were prepared. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to characterize the additives; by comparing the mechanical properties of SR composites after aging, the optimal experimental group was obtained. Besides, the action mechanism of γ-Fe2O3–CNTs on the thermal oxidative degradation of SR composite was studied by measuring the average molecular weight between crosslinking points (Mc) of SR before and after aging, as well as by detecting the degradation products of SR by thermogravimetric analysis/infrared spectrometry (TG–IR). The results indicated that γ-Fe2O3–CNTs could not only increase the initial formation temperatures of degradation products, but also decrease the concentrations of products from the oxidation and fracture of side chains of SR. All the above influences contributed to the improvement of the thermal oxidative stability of SR.