波谱学杂志 ›› 1990, Vol. 7 ›› Issue (4): 383-392.

• 研究论文 • 上一篇    下一篇

在CP/MAS条件下交联聚甲基丙烯酸甲酯中α-甲基的13C自旋-晶格弛豫

晏欣, 胡建治, 王德华, 钱保功   

  1. 中国科学院武汉物理所波谱与原子分子物理开放研究实验室
  • 收稿日期:1989-10-20 修回日期:1990-02-14 出版日期:1990-12-05 发布日期:2018-01-23
  • 基金资助:
    The project supported by National Natural Science Foundation of China

13C SPIN-LATTICE RELAXATION OF α-CH3 IN CROSSLINKED POLY (METHYL METHACRYLATES) USING CP/MAS TECHNIQUES

Yan Xin, Hu Jianzhi, Wang Dehua, Qian Baogong   

  1. Lab. of Magnetic Resonance & Atomic and Molecular Physics, Wuhan Institute of Physics, Acadenua Sinica, 430071 Wuhan, Hubei
  • Received:1989-10-20 Revised:1990-02-14 Online:1990-12-05 Published:2018-01-23
  • Supported by:
    The project supported by National Natural Science Foundation of China

摘要: 根据不同的跃迁运动和自由扩散运动模型导出了魔角旋转条件下的平均谱密度函数。从CP/MAS谱计算了样品中交联剂DVB的含量。依据实验测得的T1值计算了一系列用DVB交联的聚甲基丙烯酸甲酯中α-甲基的转动相关时间以及扩散系数。结果表明:(1)随交联剂DVB含量的增加,相关时间增加,而扩散系数下降;(2)α-甲基的转动活化能与交联剂DVB无关,并且小于从介电和力学松弛所得的值。

关键词: 自旋-晶格弛豫, 平均谱密度函数, 交联聚甲基丙烯酸甲酯

Abstract: The average spectral density functions under MAS condition were derived from various models of jump motion and models of freely diffusive motion. The contents of crosslinking agent DVB were evaluated by using CP/MAS spectra. The rotational correlation times and diffusion coefficients of α-CH3 in a series of poly (methyl methacrylates) crosslinked with DVB were calculated according to the measured T1 values. The results showed that:(1) the correlation times increase and the diffusion coefficients decrease as the contents of DVB increase, (2) the rotation activation energy of the α-CH3 is independent of the contents of DVB and less than that from dielectric and mechanical relaxations.

Key words: Spin-Lattice relaxation, Average spectral density function, Crosslinked poly (methyl methacrylates)