苯乙烯-乙烯／丁烯嵌段共聚物的二维核磁方法

Two-Dimensional NMR Measurements of the Chain Microstructure of Styrene-Ethylene/Butylene Block Copolymer

利用二维核磁方法对苯乙烯-乙烯/丁烯嵌段共聚物的链段微结构进行了定性。利用普通一维1H和13C核磁得到了共聚物分子的基本结构信息;利用1H-1H-COSY二维核磁确定了共聚物中同核氢质子之间的偶合关系;利用13C-1H-HSQC和13C-1H-HMBC二维核磁确定了共聚物异核碳氢原子的单键相关性,明确了直接相连接的C-H化学位移,为微结构的确定提供了依据。归属了苯乙烯嵌段结构中的亚甲基和次甲基的化学位移;同时归属了乙烯-丁烯嵌段链段结构中的甲基、亚甲基和次甲基的化学位移,并确定了重复单元的链段结构状态。二维核磁方法可以得到很多在普通一维核磁中难以解析的信息。二维核磁是对苯乙烯-乙烯/丁烯嵌段共聚物链结构定性的有效手段。

In this paper,the chain microstructure of a styrene-ethylene/butylene block copolymer was qualitatively studied by two-dimensional（2D） NMR.The basic structure information of the styrene-ethylene/butylene block copolymer was gained via ordinary one-dimensional 1H and 13C-NMR.The coupling of homonuclear proton was determined by 1H-1H-homonuclear chemical shift correlation spectroscopy（COSY） 2D NMR,as well as the proton chemical environment,in the copolymer.13C-1H-heternuclear singular quantum correlation（HSQC） and 13C-1H-heternuelear multiple-bond correlation（HMBC） 2D NMR were also used to obtain the single bond correlation of heteronuclear hydrocarbon atoms.The chemical shift of the C-H directly connected was clearly determined.It provided a basis for the determination of the microstructure.In the present study,we assigned the chemical shifts of the methylene and methyl in polystyrene block.The chemical shifts of the methyl,methylene and methane in ethylene-butylene block and gained the structural state of these repeat units were assigned.Some structure information which is difficult to reveal by the ordinary one-dimensional NMR spectra,can be found by two-dimensional NMR methods.2D NMR experiments are the powerful method to study the chain structure of the styrene-ethylene/butylene block copolymer.