【摘要】 为考察甲基乙烯基硅泡沫材料在不同条件下的辐射效应,开展了受压状态下材料经60Co γ射线辐照后的热老化和湿热老化实验。采用扫描电镜、傅里叶转换红外光谱仪、固体核磁共振仪、万能材料试验机和蠕变松弛试验机等手段剖析了材料微观结构和宏观性能。结果表明,不同条件下老化后甲基乙烯基硅泡沫材料的泡孔有减小的趋势。29Si交叉极化的NMR分析发现材料中有机硅链段峰的强度随吸收剂量的增大而升高,13C交叉极化的NMR分析表明γ射线辐照后材料的结构规整性有所降低。辐射后热老化样品的拉伸强度总比辐射后湿热老化样品的低,辐射老化和湿热老化的协同作用对材料的应力松弛率影响非常明显。更多还原

【Abstract】 The radiation effect of different conditions on polymethyl-vinyl siloxane foam(PMVSF)under the state of pressure was investigated.The samples were firstly irradiated by 60Co γ-ray,and then were degradated in the moist-heat environment and in the thermal oxidative environment,respectively.The correlation of PMVSF’s microstructure and macroscopic properties were determined by scanning electron microscope,Fourier transition infrared resonance,solid nuclear magnetic resonance(SNMR),universal material tester and electron creep/relaxation tester,respectively.There is a dropping trend of the pores in irradiated samples.The result of 29Si cross polarization SNMR shows that the peak intensity of organic silicon chain increases along with the increment of absorbed dose.The result of 13C cross polarization SNMR shows that the structure regularity of samples drops.It has been found that the tensile strength of irradiated samples after thermal degradation is lower than that of irradiated samples after moist-heat degradation.The synergy effect of radiation degradation and the moist-heat degradation is prominent to the samples’ stress relaxation ratio.更多还原