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合成了两个无规1,2-聚丁二烯试样(A和B)。用~(13)C-N MR波谱方法观测了间同1,2-聚丁二烯和试样A、B中侧基叔碳的贡献。运用聚烯烃结构单元近邻相互作用具有加和性这一原理,处理谱峰化学位移数据,归属了无规1,2聚丁二烯五元组序列。在此基础上,初步进行了~(13)C-NMR谱图的定量分析,考察了五元组序列的分布模式。 1,2-聚丁二烯的合成与研究为时较早。但是应用~(13)C-NMR波谱方法研究1,2-聚丁二烯分子链的序列结构还是近期的事情。Elgert通过同位素合成得到碳—13丰度达4％左右的1,2-聚丁二烯,并在67.88MH_2的磁场下记录~(13)C-N MR谱,初步归属了由侧基中两个烯碳碳核所产生的五元组各序列的共振吸收峰。对于谱峰强度的定量计算表明无规1,2-聚丁二烯分子链的立构序列服从Bernoulli分布。本工作应用Randall提出的聚合物分子链中结构单元的近邻相互作用的加和性原理,处理1,2-聚丁二烯侧基叔碳的~(13)C-NMR谱图。与此同时,通过对于谱峰强度的计算,初步研究了无规1,2-聚丁二烯的立构序列分布。
Two random 1,2-polybutadiene samples (A and B) were synthesized. The ~ (13) C-N MR spectroscopy was used to observe the contribution of meta-1,2-polybutadiene to pendant tertiary carbons in samples A and B. By using the principle that the adjacent structures of polyolefins interact with each other, the spectral peak chemical shift data are processed and belong to random 1,2-polybutadiene pentad sequence. On this basis, quantitative analysis of ~ (13) C-NMR spectra was carried out, and the distribution pattern of quintuple sequence was investigated. 1,2-polybutadiene synthesis and research earlier. However, the sequence structure of 1,2-polybutadiene molecular chain has been studied by 13C-NMR spectroscopy. Elgert synthesized 1,2-polybutadiene with a carbon-13 abundance of about 4% by isotope synthesis and recorded the ~ (13) CN MR spectra in a magnetic field of 67.88MH 2. Resonance absorption peaks of five-tuples generated by carbon-carbon nuclei. The quantitative calculation of the peak intensity shows that the stereosequence of the random 1,2-polybutadiene molecular chain obeys the Bernoulli distribution. In this work, the ~ (13) C-NMR spectra of 1,2-polybutadiene pendant tertiary carbons were processed using Randall’s principle of summation of the neighbors’ interactions of the structural units in the polymer chain. At the same time, through the calculation of the peak intensity, the stereosequence distribution of random 1,2-polybutadiene has been studied.