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A Study on Higher-order Structures and Dynamics of Ionic Aggregates in Ionomers

离聚物中离子聚集体的高阶结构和动力学研究

基本信息

批准号：
11695047
负责人：
TSUJITA Yoshiharu
金额：
$ 3.71万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

The ionomers are defined as polymers with non-polar backbones containing up to about 10 mol% salt groups of carboxyl or sulfonic acids. It can be, therefore, said that the ionomers is one of the hybrid materials. The ionomers can form the ionic aggregates, which improve the mechanical properties of them. In cadmium salt ethylene ionomers, it is confirmed that the ionic aggregates are also formed, from SAXS analysis. The size of the ionic aggregates of this ionomer becomes larger with the degree of neutralization. This is a different point in comparing with the other ethylene ionomers using divalent metal cations such as zinc cation. The ^<113>Cd MAS spectra with and without CP experiment for cadmium salt ethylene ionomer at various temperatures were observed. In CP/MAS spectra, a very broad peak is only observed at low temperatures. It can be seen that these spectra consists of several peaks appeared at about 120 to -50 ppm. Consequently, the broadening of this peak may be mainly caused by the very wide distribution of micro structures at surroundings of^<113>Cd nuclei in the ionic aggregates. At higher temperatures, this CP/MAS peak disappears, indicating that the mobility of ^<113>Cd nuclei close to the dipolar decoupling frequency and/or the CP efficiency becomes too low to detect the CP signals because of the high mobility of 1H nuclei at surroundings of ^<113>Cd. That is, the ionic aggregates in cadmium salt ethylene ionomers leads to mobile state from immobile one by heating. On the contrary, the ^<113>Cd MAS NMR spectra without CP experiment are observed only at high temperatures, and the width of observed peaks are relatively narrow compared with CP/MAS. In addition, the ^<113>Cd NMR chemical shift changes by temperature. These findings indicate that the mobility of the ionic aggregates is high at higher temperatures.

离聚物定义为具有非极性主链的聚合物，所述非极性主链含有至多约10摩尔%的羧基或磺酸盐基团。因此，可以说离聚物是杂化材料之一。离聚体可以形成离子聚集体，从而提高材料的力学性能。在镉盐乙烯离聚物，它被证实，离子聚集体也形成，从SAXS分析。该离聚物的离子聚集体的尺寸随着中和度而变大。这是与使用二价金属阳离子如锌阳离子的其它乙烯离聚物相比的不同点。本文<113>观察了不同温度下镉盐乙烯离聚体的~（13）Cd MAS谱，并进行了CP实验和非CP实验。在CP/MAS谱中，仅在低温下观察到非常宽的峰。可以看出，这些光谱由在约120至约50 ppm处出现的几个峰组成。因此，该峰的加宽可能主要是由离子聚集体中^ Cd核周围非常宽的微结构分布引起<113>的。在更高的温度下，该CP/MAS峰消失，表明<113>接近偶极去耦频率的^ Cd核的迁移率和/或CP效率变得太低而不能检测CP信号，因为在^ Cd周围的1H核的高迁移率<113>。即镉盐乙烯离聚物中的离子聚集体通过加热由非移动的态转变为移动的态。与之相反，<113>未进行CP实验的~（13）Cd MAS NMR谱仅在高温下观察到，且峰宽较CP/MAS窄。此外，1H <113>Cd NMR化学位移随温度变化。这些发现表明，在较高的温度下，离子聚集体的流动性高。