Temperature scanning FTIR analysis of hydrogen bonding states of various saccharides in amorphous matrixes below and above their glass transition temperatures
Temperature scanning FTIR analysis of hydrogen bonding states of various saccharides in amorphous matrixes below and above their glass transition temperatures
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DOI：
10.1021/jp057527o
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发表时间：
2006-08-10
影响因子：
3.3
通讯作者：
Nakanishi, Kazuhiro
中科院分区：
文献类型：
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作者：
Imamura, Koreyoshi;Sakaura, Keisuke;Nakanishi, Kazuhiro
对各种无定形糖基质进行温度扫描傅里叶变换红外光谱（TS-FTIR），以研究无定形糖基质的玻璃化转变温度T-g与基质中氢键性质之间的关系。通过风干糖水溶液制备无定形糖基质，并使用对应于在3400 cm（-1）附近的O-H伸缩振动的IR带的峰位置在不同温度下评价基质中氢键的形成程度。T-g值随着T-g处O-H伸缩振动的峰位置的增加而增加，并且与温度增加（从25 ° C）到T-g值的峰位移的幅度相当好地相关。这表明，无定形糖基质具有更高的热阻，其中链段通过较少的氢键固定。糖苷键在很大程度上有助于吡喃糖环片段的限制，而不是氢键。随着吡喃糖环的聚合度增加，将基质保持在固定位置所需的氢键形成程度降低。然而，糖苷键对吡喃糖环的限制程度根据类型而变化：α-1，1和-1，6糖苷键施加的限制分别是所有糖苷键类型中最紧密和最灵活的。
Temperature scanning Fourier transform infrared, TS-FTIR, spectroscopy of various amorphous sugar matrixes was conducted to investigate the relationship between the glass transition temperature, T-g, of an amorphous sugar matrix and the nature of the hydrogen bonds in the matrix. An amorphous sugar matrix was prepared by air-drying an aqueous solution of sugar, and the degree of formation of hydrogen bonds in the matrix was evaluated at different temperatures using the peak positions of the IR band corresponding to the O-H stretching vibration at around 3400 cm(-1). The T-g value increased with increasing peak position of the O-H stretching vibration at T-g and were correlated reasonably well with the magnitude of the peak shift by the temperature increase (from 25 degrees C) to the T-g value. This demonstrates that the amorphous sugar matrix, in which the segments are fixed by fewer hydrogen bonds, has a higher thermal resistance. The glycosidic linkage largely contributes to the restriction of the segments, pyranose ring, rather than a hydrogen bond. As the degree of polymerization of pyranose rings increases, the degree of hydrogen bond formation needed to hold the matrix in a fixed position decreases. However, the magnitude of the restriction of pyranose rings by a glycosidic linkage changes depending on the type: the restrictions imposed by alpha-1,1 and -1,6 glycosidic linkages are the tightest and most flexible of all of the types of glycosidic linkages, respectively.