Epoxy-POSS/silicone rubber nanocomposites with excellent thermal stability and radiation resistance

Due to the rigid Si-O-Si backbone, silicone rubber (SR) have a widespread application in extreme environment such as high temperature and high-level radiation. However, the radiation stability of SR still does not meet the practical needs in special radiation environments. Herein we prepared epoxy POSS(ePOSS)/SR nanocomposites with excellent thermal stability and radiation resistance. As a physical crosslinking point in the SR, addition of small amount of ePOSS not only enhanced the mechanical properties of the matrix, but also improved its thermal stability greatly due to their good compatibility. ePOSS/SR had higher radiation stability in air than SR owing to the inhibition of radiation oxidation by ePOSS, and the yield of main gaseous radiolysis products (CH4, H2, CO and CO2) of SR and ePOSS/SR nanocomposites was determined. By analyzing the changes of chemical structure, thermal properties and mechanical properties of the ePOSS/SR nanocomposite, combined with the characteristics of gas products after γ-irradiation, the radiation induced crosslinking and degradation mechanism of the nanocomposites was proposed comprehensively.