| 结晶PMMA的NMR研究 |
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| 引用本文： | 易菊珍,冯汉桥.结晶PMMA的NMR研究[J].波谱学杂志,1999,16(1):40-43. |
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| 作者姓名： | 易菊珍 冯汉桥 |
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| 作者单位： | 中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室, 武汉 430071 |
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| 摘 要： | 用NMR方法和DSC技术研究了结晶聚甲基丙烯酸甲酯(PMMA)性质和玻璃化转变温度,并与无定形PMMA作了比较.通过13C CPMAS谱,观察到了结晶PMMA与无定形PM MA的谱的线形,线宽,化学位移都十分类似,其中α-CH3分裂为两个峰,我们将它归属为γ旁式效应所对应的反式和旁式构象.而反门控碳谱显示PMMA中有四种状态,即等规PMMA结晶态和无定形态,间规PMMA结晶态和无定形态.通过测定T2(H)和旋转坐标系中质子的自旋晶格弛豫时间T1ρ(H),我们分别得到了两T2(H)值和两个T1ρ(H)值,对应于晶区与非晶区,而且其含量分别与反门控碳谱积分所得含量一致.
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| 关 键 词： | NMR弛豫时间 DSC 玻璃化转变温度 结晶PMMA |
| 收稿时间： | 1998-10-07 |
THE NMR STUDY OF CRYSTALLINE PMMA |
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| Yi Juzhen,Feng Hanqiao.THE NMR STUDY OF CRYSTALLINE PMMA[J].Chinese Journal of Magnetic Resonance,1999,16(1):40-43. |
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| Authors: | Yi Juzhen Feng Hanqiao |
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| Institution: | State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071 |
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| Abstract: | The relaxation character and glass transition temperature of crystalline poly (methyl methacrylate)(PMMA) have been studied by means of NMR and DSC techniques. Compared with amorphous PMMA, the 13C CP/MAS spectra of the crystalline one has similar band shape, band width and chemical shifts. α-CH3 carbon resonance exhibits two bands with a very asymmetrical shape, which may be related to conformational structure in sequence of the so-called γ-gauche effect. The two values of the proton spin-lattice relaxation time in rotating frame T1ρ (H) observed correspond to amorphous and crystaline structure respectively dectected by inverse gated decoupling. Aggregated structure wasn't detected by NMR means. |
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| Keywords: | DSC |
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