关键词: 取代基效应方法, 乙烯-α-烯烃共聚物, 序列结构, 定量分析, 普适方法

Abstract: In analysis of sequence structure of ethylenc-α-olefine copolymers methylene (CH₂) βγ and γδ which present the inverse units of comonomer in chain of the copolymer are assigned to VV dyad and EEV triad, respectively. At the same time, both CH₂ δδ and δδ⁺ are assigned to EE dyad. But partition of intensity Iδ⁺δ⁺ characterizing long sequence of ethylene between EE dyad and EEE triad is a key task for treating the sequence distribution of the copolymer. In fact, intensity Iδ⁺δ⁺ should not be divided equally. In order to revise it deduction is performed by Bovey's relationship and Randall's statistical method of polymer sequence. Therefore, the exact representation, exact and approximate solution of revisionary value A are all obtained successfully. The approximate solution obtained under condition of regular chain is identical with Ray's result. When content of comonomer in copolymer is low, the partitions of I_δ⁺δ⁺ between EE and EEE is almost equal.
In level of dyad and triad, there are 13 peaks altogether on the ¹³C NMR spectrum of ethylenc-α-olefine copolymer, where 10 peaks belong to CH₂ and the other 3 to CH. A set of formula calculating sequence distribution could be proposed directly by using those intensities of peaks mentioned above. All information of copolymer sequence structure could be obtained undoubtedly based on it. Hence the method presented here is a satisfactory and universal for studying sequence structure of ethylene-α-olefine copolymers.

Key words: Substituent chemical shift (SCS), Ethylene-α-olefine copolymen, Sequence structure, Quantitative analysis, Universal method