Experimental Study On Outgassing Performance Of Glass Fiber Paper

The outgassing of materials is the main factor leading to the deterioration of vacuum in the sandwich of low temperature insulation containers.Accurate testing of the outgassing rate of thermal insulation materials,mastering the law of outgassing is the basis for studying the influence of materials on the vacuum environment,and it is of great significance for the prediction of vacuum life.According to the national standard GB/T31480-2015,the outgassing rate of glass fiber paper was 1.25×10^-9 Pa·m³/?s·g?by pressure rise method.The outgassing rate measured under different test modes was compared and analyzed.The outgassing rate of a glass fiber paper under different vacuuming time and different vacuum pressure was studied.It was found that the outgassing rate of the material was not only related to the vacuuming time,but also related to the vacuum pressure of the material during vacuuming.The outgassing obtained by different test methods under pressure is significantly different.The results show that the outgassing rate measured under the same vacuum pressure has better consistency than the gas venting rate measured under the same vacuuming time;compared with the vacuuming stage,the static venting after the vacuuming is completed The outgassing rate measured in the stage is more valuable in practical applications.The glass fiber paper was heated while pumping,and the effect of baking on the outgassing of the material was studied.The material outgassing rate and outgassing composition at different baking temperatures were compared and analyzed.It is found that the outgassing rate tested at 120°C is closer to 150°C.Although the baking temperature is effective for accelerating the outgassing of material,the ratio of each gas component measured at different heating temperatures is substantially unchanged.The results show that the baking temperature of 120°C can achieve good heating effect through lower heating cost.The heat treatment has little effect on the gassing component of glass fiber paper.After pumping,the main outgassing component of glass fiber paper is still water vapor.