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首页> 外文会议>NMR spectroscopy of polymers: Innovative strategies for complex macromolecules >Dependence of the Amount of Xe Sorption on the ~(129)Xe NMR Chemical Shift in Glassy Polymers
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Dependence of the Amount of Xe Sorption on the ~(129)Xe NMR Chemical Shift in Glassy Polymers

机译：Xe吸附量对玻璃态聚合物〜（129）Xe NMR化学位移的依赖性

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Microvoids in glassy polymers are considered to be correlated with unrelaxed volume (so-called "excess free volume"). In this article, the microvoids were investigated by Xe sorption and ~(129)Xe NMR measurements. The Xe sorption isotherms of glassy polymers were successfully interpreted by the dual-mode sorption model composed of Henry and Langmuir sorption sites. ~(129)Xe NMR chemical shifts of ~(129)Xe in glassy polymers showed a non-linear low-field shift with increasing amount of Xe sorption because of fast exchange of Xe atoms between the two sites. From the ~(129)Xe NMR chemical shift, we could determine the mean size of the microvoids. In several polymers, this methodology was examined from three perspectives of free volume, viz., thermal expansion, miscibility with reduced free volume in a polymer blend, and specific crystalline structure. From these findings, ~(129)Xe NMR spectroscopy is shown to be a powerful technique to determine the mean size of microvoids in glassy polymers.
机译：玻璃状聚合物中的微孔被认为与未松弛的体积（所谓的“过量自由体积”）相关。在本文中，通过Xe吸附和〜（129）Xe NMR测量研究了微孔。玻璃质聚合物的Xe吸附等温线成功地通过由Henry和Langmuir吸附位点组成的双模吸附模型进行了解释。由于两个位置之间Xe原子的快速交换，玻璃状聚合物中〜（129）Xe的〜（129）Xe NMR化学位移显示出随着Xe吸附量增加的非线性低场位移。从〜（129）Xe NMR化学位移，我们可以确定微孔的平均大小。在几种聚合物中，从自由体积，即热膨胀，聚合物共混物中自由体积减少的可混溶性和特定的晶体结构的三个角度检查了该方法。从这些发现，〜（129）Xe NMR光谱被证明是确定玻璃状聚合物中微孔平均尺寸的强大技术。

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