Chain dynamics in elastomers as investigated by proton multiple-quantum NMR
Chain dynamics in elastomers as investigated by proton multiple-quantum NMR
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DOI：
10.1021/ma052567b
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发表时间：
2006-04
期刊：
影响因子：
5.5
通讯作者：
K. Saalwächter;A. Heuer
中科院分区：
文献类型：
--
作者：
K. Saalwächter;A. Heuer
利用静态质子多量子实验研究了弹性体中链段动力学和协同动力学对核磁共振实验时间演化的影响。一种新的实验策略，以及一个简单的旋转扩散模型的Monte Carlo模拟被用来调查的Andersen-韦斯近似，我们的分析解决方案的基础上的适用性。在温度相关实验的基础上，证明了迄今为止用于解释NMR实验的最流行的模型之一的有效性。该模型，这是基于缓慢的旋转扩散的preaveraged残余耦合张量，细化明确考虑的时间尺度的快速节段过程平均的intrasegmental偶极耦合向一个平台值，这是相关的链序参数与拓扑限制的化学和物理交联。模型的基础上指数或幂律损失的相关性示出p…
The influence of segmental and cooperative dynamics in elastomers on the time evolution in NMR experiments is considered using static proton multiple-quantum experiments. A novel experimental strategy as well as Monte Carlo simulations of a simple rotational diffusion model is used to investigate the applicability of the Andersen−Weiss approximation, upon which our analytical solutions are based. On the basis of temperature-dependent experiments, the validity of one of the most popular models used so far for the interpretation of NMR experiments is disproved. This model, which is based on slow rotational diffusion of a preaveraged residual coupling tensor, is refined by explicit consideration of the time scale of fast segmental processes which average the intrasegmental dipolar coupling toward a plateau value that is related to the chain order parameter associated with topological restrictions by chemical and physical cross-links. Models based on exponential or power-law loss of correlation are shown to p...