辐照对不同形态聚乙烯形成的两种交联链结构的定量影响

THE EFFECT OF IRRADIATION ON A CHANGE IN QUANTITY OF TWO TYPES OF RADIATON INDUCED CROSS-LINKS IN HDPE WITH DIFFERENT MORPHOLOGY.

本文用^(13)C高分辨核磁共振方法表征并研究了两种高密度聚乙烯经^(60)Coγ线辐射交联后的网络结构。首次直接观测到无论是固态或融态下聚乙烯经辐射后都形成具有H-型和Y-型两种网状结构的交联物。辐射过程中伴随的其他结构单元的变化也被检测到。定量分析的结果表明:两种交联链的生成G_H和G_Y值与聚乙烯辐照时存在的形态有关,在较高温度或融熔态下H-型交联易于形成,而室温附近Y-型交联链的生成量为主要。这些实验结果对辐照聚乙烯的交联机制引入了新的看法,同时也为今后研究其他高分子交联链结构提供了一种新的更直接的方法。

High-resolution solution ^(13)C NMR spectra on radiation cross-linking in high density polyethylene by ^(60)Co γ-rays has been observed. Two of thecross-linking new structural units identified. in the present study for irradiated polye-thylene are H- and Y-type, which formed during irradiation of polyethylene in va-cuum both in the solid state and in the molten state. Other radiation induced structural changes in the samples have been also detected.It is show that the concentration of Y-type formed during irradiation in vacuum inthe solid state is greater than that of H-type, while H-type formed during irradiationin vacuum in the molten state is greater than Y-type. The results of this study haveled to new insights into mechanism of radiation induced linking of polyethylene, andprovide means of characterization of irradiated polymer.