Department of Engineering Science, Osaka Electro-Communication University Neyagawa, Japan.
Front Chem. 2014 Mar 12;2:10. doi: 10.3389/fchem.2014.00010. eCollection 2014.
Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH…OH and C=O…HO types of hydrogen-bonds were found around the glass transition temperature of 80°C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O…HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH…OH type of hydrogen-bonds induces the association of the C=O…HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature.
通过温度依赖的红外（IR）光谱研究了聚（2-羟乙基甲基丙烯酸酯）（PHEMA）中的氢键结构。在 80°C 的玻璃化转变温度附近，发现了与 OH…OH 和 C=O…HO 类型氢键相关的光谱变化。随着温度的升高，羟基之间的氢键逐渐解离。相比之下，在玻璃化转变温度附近观察到羰基带的不连续变化。在玻璃化转变温度以上的温度下，发现了 C=O…HO 类型氢键的缔合。从本研究中可以得出结论，在玻璃化转变温度以下的聚合物基质中，每个侧链末端的羟基之间的氢键抑制了主链的迁移性，而 OH…OH 类型氢键的解离诱导了 C=O…HO 类型氢键的缔合。结果，氢键结构的变化在玻璃化转变温度下诱导了主链的迁移性。
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