Radiation effect of 150 keV protons on methyl silicone rubber reinforced with MQ silicone resin

The damage of methyl silicone rubber reinforced with MQ silicone resin under 150 keV proton irradiation was studied using a space combined irradiation simulator. The experimental results show that there are aging cracks appearing on the surface of specimens after irradiation. Under the proton fluence lower than approximately 1014 cm-2, the hardness and tensile strength increase with the fluence while the elongation at rupture decreases, the cross-linking density increases with the fluence, which increasing the storage modulus and moving the glass temperature to higher temperatures. IR analysis indicates that the Si-O content increases, implying that the major damage of the silicone rubber is caused by cross-linking. With further increasing the fluence, the changes in hardness, tensile strength, elongation at rupture, cross-linking density, storage modulus, glass temperature and Si-O content show the opposite tendency to those for the fluence lower than 1014 cm-2. In the latter case, the decrease of Si-O content indicates that the major damage of the silicone rubber is caused by degradation. With the increase of proton fluence, the mass loss ratio of the silicone rubber increase due to volatile substances generated by the degradation of silicone rubber subjected to proton irradiation in the high vacuum environment