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Precise Molecular Weight Determination and Structure Characterization of End-functionalized Polymers:An NMR Approach via Combination of One-dimensional and Two-dimensional Techniques 被引量:1
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作者 dong-xue chen ling-feng gao +1 位作者 李晓虹 屠迎锋 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2017年第5期681-692,共12页
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... 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 (dl) 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 dl setting to achieve quantitative NMR analysis. 展开更多
关键词 NMR spectroscopy molecular weight determination Quantitative NMR analysis 2D NMR
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