DIELECTRIC AND VISCOELASTIC STUDIES OF POLY (ETHYL METHACRYLATE) CONTAINING CHOLESTERIC COMPOUNDS
DIELECTRIC AND VISCOELASTIC STUDIES OF POLY (ETHYL METHACRYLATE) CONTAINING CHOLESTERIC COMPOUNDS
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DOI：
10.1002/pi.4990240106
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发表时间：
1991
影响因子：
3.2
通讯作者：
D. D. Deshpande-D.;C. Basu;M. Pandya
中科院分区：
文献类型：
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作者：
D. D. Deshpande-D.;C. Basu;M. Pandya
通过介电和动态机械光谱研究了含有少量胆固醇添加剂的聚甲基丙烯酸乙酯（PEMA）。将纯 PEMA 和 PEMA + 添加剂系统的介电数据拟合到 WLF 方程中。使用从纯 PEMA 数据获得的 WLF 常数，确定 PEMA + 添加剂系统的 To 值，以获得实验点与 WLF 曲线的最佳拟合。与纯 PEMA 相比，所有 PEMA + 添加剂系统的 tan δmax（介电和机械）值都转向更高的温度。在玻璃态区域，PEMA+添加剂体系的模量高于纯PEMA。 PEMA + 添加剂系统的粘度测量表明存在一些相互作用。聚合物+添加剂体系的 FTIR 光谱显示羰基键频率没有变化。 Tg 向更高温度的转变表明该区域的链运动受到这些添加剂的极大阻碍，其原因可能是添加剂分子在聚合物基体中的拟合或排列。
Poly(ethyl methacrylate) (PEMA) containing small amounts of cholesteryl additives was studied by dielectric and dynamic mechanical spectroscopy. Dielectric data from pure PEMA and PEMA + additive systems were fitted to the WLF equation. Using the WLF constants obtained from the data for pure PEMA, the To values for PEMA + additive systems were determined in order to get the best fit of the experimental points to the WLF curve. Values of tan δmax (dielectric and mechanical) for all the PEMA + additive systems shift to higher temperatures compared with that for pure PEMA. In the glassy region, the moduli of PEMA + additive systems are higher than that of pure PEMA. Viscometric studies of PEMA + additive systems indicate the presence of some interaction. FTIR spectra of the polymer + additive systems show no shift in carbonyl bond frequency. The shift of Tg to higher temperatures indicates that chain motion in this region is hindered greatly by these additives and the reason for this may be the fitting or aligning of the additive molecules in the polymer matrix.