节点文献
低密度聚乙烯光引发交联机理Ⅲ.模型化合物n-C_(24)H_(50)的 ̄(13)CNMR研究
MECHANISM OF PHOTOINITIATED CROSS-LINKING OF LOW DENSITY POLYETHYLENE Ⅲ.13C NMR Studies of n-C24H50 as a Model Compound
【摘要】 用溶液高分辨 ̄(13)CNMR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-C_(24)H_(50)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-CH_2和β-CH_2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-CH_2和β-CH_2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.
【Abstract】 H-type cross-links produced by photoinitiated cross一linking of n-C24H50 as amodel compound of polyethylene in the presence of benzophenone asphotoinitiator have been studied for the first time by solution-state 13C NMRspectroscopy.Resonance lines assigned to the CH,α-CH2,andβ-CH2 carbons as-sociated w1th H-type cross-links have been observed and identified for thephotocross-linked samples,and compared with data from the model compound andγ-irradiation cross-linking of n-paraffins and polyethylene.A new resonance lineat 40.83 ppm is attributed to methine carbons in H-links.The other two new reso-nances 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 tobe 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;
- 【文献出处】 波谱学杂志 ,CHINESE JOURNAL OF MAGNETIC RESONANCE , 编辑部邮箱 ,1995年03期
- 【分类号】O632.12
- 【被引频次】5
- 【下载频次】64