Chinese Journal of Magnetic Resonance ›› 1991, Vol. 8 ›› Issue (1): 63-72.

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SUBSTITUENT CHEMICAL SHIFT (SCS) AND THE SEQUENCE STRUCTURE OF ETHYLENE-α-OLEFINE COPOLYMERS Ⅲ. Quantitative Analysis

Zhou Zinan, Tian Wenjing, Wu Shengrong, Zhang Jianguo, Pei Fengkui   

  1. Labratory of Polymer Physics, Changchun Institute of Applied Chemistry, Academia Sciences, Jilin, Changchun 130022, People's Republic of China
  • Received:1990-04-02 Revised:1990-10-01 Published:1991-03-05 Online:2018-01-20

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 Iδ+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