The Effect Of Graphene And Its Reduction Degree On The Thermal Oxidative Stability Of Silicone Rubber

In this paper, graphene oxide(GO) was prepared by modified Hummers method and reduced graphene oxide(RGO) with various reduction degree were obtained by controlling the temperature during thermal reduction. Meanwhile, different kinds of silicone rubber(SR) composite materials were prepared by incorporating these particles. Transmission electron microscopy(TEM), Raman spectra, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) were used to character the obtained particles. On the other hand, the action mechanism of the particles on the thermal oxidative degradation of SR composite was studied by measuring the mechanical properties and the average molecular weight between crosslinking points(Mc) of SR before and after aging, as well as by detecting the degradation process of SR by thermo- gravimetric analysis(TG).The results indicated that graphite and GO had no obvious impact on the mechanical properties and the thermal oxidative stability of silicon rubber. In comparison, RGO could increase the mechanical properties of SR significantly: the tensile strength of RGO/SR was nearly three times to that of blank sample and its elongation at break was nearly twice to that of blank sample. Furthermore, RGO could also decrease the amounts of products from the oxidation and side chains fractures of SR, giving rise to the improvement of the initial formation temperatures of degradation products. Compared with the blank sample, the whole TG curve of RGO/SR was shifted to a higher temperature of about 54.3°C. In addition, graphene has excellent thermal conductivity, and its large surface area can enhance the interfacial interaction with SR and provide lower interfacial thermal resistance, which can improve the thermal oxidative stability of SR. What's more, the reduction degree of GO can be tailored by altering the temperature of thermal treatment, and it turned out that the higher the reduction degree of grapheme was, the better the proporties of SR composites could be. This phenomenon might be attributed to the fact that, when there is a higher degree of reduction, there are less lamella defects, larger of lamellar spacing as well as higher degree of disorder.