Precise molecular weight determination and structure characterization of end-functionalized polymers: An NMR approach via combination of one-dimensional and two-dimensional techniques

被引:0
作者
Dong-xue Chen
Ling-feng Gao
Xiao-hong Li
Ying-feng Tu
机构
[1] Soochow University,Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials,
来源
Chinese Journal of Polymer Science | 2017年 / 35卷
关键词
NMR spectroscopy; Molecular weight determination; Quantitative NMR analysis; 2D NMR;
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中图分类号
学科分类号
摘要
We present here the application of one-dimensional and two-dimensional NMR techniques to characterize the structure of methoxyl end-functionalized polystyrenes (PS). The peaks in 1H-NMR spectra corresponding to main-chain, side-chain and chain-end groups are assigned by 1H-1H gCOSY, 1H-13C gHSQC and gHMBC spectra. For the first time, the spin-lattice relaxation time (T1) of protons of the chain-ends is revealed to be affected more by polymer molecular weight (MW) than by the protons of the main-chains and the side-chains (almost independent from MW). As a result, a much higher delay time (d1) for chain-ends (d1 > 20T1) is needed for quantitative NMR measurement when using end-group estimation method to obtain the MW of PS, which is in accordance with the value estimated by GPC. An improved method for the polymer MW determination is established, by combination of different NMR techniques to distinguish the peaks, and a large d1 setting to achieve quantitative NMR analysis.
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页码:681 / 692
页数:11
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