取代基效应(SCS)与乙烯-α-烯烃共聚物的序列结构——7.氢化丁苯共聚物(HBS)

测定了两个氢化丁苯共聚物样品的¹H、¹³C NMR谱。通过处理文献中的¹³C NMR谱数据得到了-C₂H₅和-C₆H₅的SCS参数。利用乙烯-α-烯烃共聚物的SCS方法结合DEPT NMR实验技术重新归属了该共聚物的¹³C NMR谱。明确指出,氢化丁苯共聚物分子链中主链任何一个乙烯单元的两个CH₂在序列分布上分属于二元组和三元组。CH则用三元组来表征。最后,对HBS共聚物的序列分布进行了计算。

SUBSTITUENT CHEMICAL SHIFT (SCS)AND THE SEQUENCE STRUCTURE OF ETHYLENE-α-OLEFINE COPOLYMERS——7. Hydrogenated Butadiene-Styrene Copolymer

Two hydrogenated butadiene-styrene copolymer (HBS) samples are studied by ¹H NMR and ¹³C NMR by using JEOL-FX100 NMR and Varian UNITY-400 superconductive spectrometer. The SCS parameters of ethyl (-C₂H₅) and benzyl (-C₆H₅) are obtained by dealing with the ¹³C NMR data from references. The ¹³C NMR spectrum of HBS is reassigned by using the SCS method of ethylene-α-olefin copolymers and the DEPT NMR experiment. It is pointed out that the two methylenes of any ethylene unit in the main chain of HBS belong to dyad and triad respectively. The methine in the main chain is expressed by triad.Finally the sequence distribution of dyad and triad is calculated. The molar composition of styrene, butene and ethylene unit in HBS calculated from ¹³C NMR spectrum is consistant with that calculated from ¹H NMR spectrum.