波谱学杂志 ›› 1995, Vol. 12 ›› Issue (3): 299-308.

• 研究论文 • 上一篇    下一篇

低密度聚乙烯光引发交联机理Ⅲ.模型化合物n-C24H5013C NMR研究

瞿保钧, 徐云华, 鲁非, 瞿欣   

  1. 中国科技大学结构成分分析开放实验室, 合肥 230026
  • 收稿日期:1994-04-21 修回日期:1994-10-05 出版日期:1995-06-05 发布日期:2018-01-17
  • 基金资助:
    国家自然科学基金,国家教委留学回国人员资助费支持项目

MECHANISM OF PHOTOINITIATED CROSS-LINKING OF LOW DENSITY POLYETHYLENE Ⅲ.13C NMR Studies of n-C24H50 as a Model Compound

QU Baojun, Xu Yunhua, Lu Fei, Qu Xin   

  1. Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
  • Received:1994-04-21 Revised:1994-10-05 Online:1995-06-05 Published:2018-01-17

摘要: 用溶液高分辨13C NMR谱首次研究了由二苯甲酮(BP)光引发低密度聚乙烯模型化合物直链烷烃n-C24H50交联所产生的H型交联点的结构特征.现已检测和鉴定了光交联样品中与H型交联点相联系的-CH,α-CH2β-CH2上碳的共振谱线,其数据与H型交联点模型化合物、γ-辐射交联正烷烃和聚乙烯所得到的结果符合得很好.在40.83ppm处出现的一个新峰可指认为H型文联点的次甲碳,其相应的31.57和28.37ppm处的另外两个新峰分别指认为相邻的α-CH2β-CH2上碳的共振.本工作中的定量研究表明:在真空和熔融态条件下莱外光照3-5min的样品中H型交联点的数目据估计为每10000个碳原子8.5~11.0个.

关键词: 13C NMR, 紫外辐照, 模型化合物, 正烷烃, 交联点

Abstract: H-type cross-links produced by photoinitiated cross一linking of n-C24H50 as a model compound of polyethylene in the presence of benzophenone as photoinitiator have been studied for the first time by solution-state 13C NMR spectroscopy.Resonance lines assigned to the CH,α-CH2,and β-CH2 carbons associated with H-type cross-links have been observed and identified for the photocross-linked samples,and compared with data from the model compound and γ-irradiation cross-linking of n-paraffins and polyethylene.A new resonance line at 40.83 ppm is attributed to methine carbons in H-links.The other two new resonances at 31.57 ppm and 28.37 ppm are assigned to α-CH2 and β-CH2,respectively.The quantitative studies in this work show that the number of H-links is estimated to be 8.5-11.0 per 10000 carbon atoms for samples UV-irradiated in vacuum in the melt for 3-5min.

Key words: 13C NMR, UV irradiation, Paraffin, Model compound, Cross-links