【摘要】 用正电子寿命谱(PALS)研究了γ辐射交联和紫外光交联聚乙烯(PE),结果表明,它能有效地检测PE交联过程中交联度、结晶度的变化和影响以及氧的影响,并且发现PALS对辐射交联过程中微量氧参与的反应是非常敏感的.观察到光交联PE的PALS强度变化规律与γ辐射交联相反,这与交联样品的制备过程和紫外光使光引发剂的强吸电子基团羰基转变成弱吸电子基团羟基有关.还利用双符合多普勒展宽谱的参数佐证了PALS结果中oPs拾取湮灭强度的变化规律与辐照过程中氧的影响.更多还原

【Abstract】 Positron annihilation lifetime spectroscope(PALS) was applied to investigate the micro-structural changes of polyethylene(PE) which was irradiated by γ-ray or ultraviolet radiation, the spectra were decomposed into three lifetime components using PATFIT package. Then it was found that the shifts of the degree of cross linking and crystallinity were detected effectively in samples. Moreover, a small quantity of oxygen, which involved in the cross-linking process, was measured sensitively by PALS. The regularity of positron lifetime intensity vs radiation intensity in γ irradiated sample was opposite to that in ultraviolet irradiated one, which is due to the preparation methods of samples and the change of polar functional group in initiator. Furthermore, contrastive patterns were studied by positron doppler broaden(DB) method and the results were agreed well with PALS data mentioned above.更多还原