The Effect Of Vacuum Thermal Cycling And Irradiation On The Airtight Material

This paper investigates the vaccum gassing behavior of TR, HY, TPUY, TPU airtight material and the vacuum thermal cycling and irradiation effects on TR, TPUY, TPU airtight material by the means of vaccum gassing, vacuum thermal cycling and the space irradiation simulation test.The result shows that, the total mass loss of HY silicone rubber is the highest and TPUY thermoplastic polyurethane is the lowest,in the meantime, the collected volatile condensable materials of TR silicone rubber is the highest and TPUY thermoplastic polyurethane is the lowest among the four kinds of airtight materials. The mass loss rate of TR,TPUY and TPU airtight materials increase gradually with the increase of vacuum thermal cycling times. At the beginning of the vacuum thermal cycling, the mass loss rate increases rapidly, but the mass loss rate increases slowly with the increase of cycling times.The tensile properties of three kinds of airtight material have no significant changes after 80 cycles of vacuum thermal cycling, the changes of tensile strength all are not more than 2.0% and breaking elongation rates all are less than 8.9%.The color of TPUY and TPU thermoplastic polyurethane changes from semitransparent and transparent state to yellow, but the color shows no significant change for TR silicone rubber, which is irradiated by electron and ultraviolet irradiation. After high fluence electron irradiation, the color of TPUY and TPU thermoplastic polyurethane turns to yellow obviously, TR silicone rubber changes from pale yellow to deep yellow. After comprehensive irradiation, the tensile strength of TR silicone rubber decreases 34.82%, TPUY thermoplastic decreases 9.40%, TPU thermoplastic polyurethane decreases 32.96% compared with the original samples. After high fluence electron irradiation, the tensile strength of TPUY and TPU thermoplastic polyurethane decreases 45.88% and 42.54%, respectively, the tensile strength of TR silicone rubber increases 6.92% compared with the original samples. The two types of irradiation situation have little influence on the elongation at break of the three kinds of airtight materials. The mechanism analysis is carried out by electron paramagnetic resonance and contact angle t est. The test results show that, the irradiation induces the formation of free radical and the decrease of surface contact angle of three kinds of airtight materials.