Caccamo Maria Teresa, Magazù Salvatore
Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Dell'Università di Messina, Italy.
Appl Spectrosc. 2017 Mar;71(3):401-409. doi: 10.1177/0003702816662882. Epub 2016 Oct 1.
Infrared spectra were collected on mixtures of ethylene glycol (EG) and polyethylene glycol 600 (PEG600) as a function of weight fraction from pure EG to pure PEG600. In this paper, it will be shown that while the OH vibrational contribution drastically reduces its center frequency from 3450 cm to 3300 cm in the weight fraction range 0-25%, the displacement of the mixture spectral features of the mixtures from ideal behavior, i.e., in the absence of interaction, shows the presence of a non-ideal mixing process. Furthermore, wavelet cross-correlation analysis of the registered pairs of spectra and of the intramolecular O-H stretching contributions reveals how the addition of a small amount of pure EG to PEG600 dramatically influences the structural properties of the polymeric matrix, owing to an increase the intermolecular connectivity. In particular, the wavelet cross-correlation parameters, evaluated between each pair of the registered data as a function of weight fraction, in a linear-logarithmic plot, reveals an inflection point for a weight fraction of about 25% of EG, which confirms that, within the three-dimensional networks of hydrogen-bonded EG-PEG600 molecules, a key role is played by EG in determining an increase in the hydrogen-bond network density.
收集了乙二醇（EG）和聚乙二醇600（PEG600）混合物的红外光谱，其作为从纯EG到纯PEG600的重量分数的函数。本文将表明，虽然在0-25%的重量分数范围内，OH振动贡献使其中心频率从3450 cm急剧降低到3300 cm，但混合物光谱特征相对于理想行为（即不存在相互作用时）的位移表明存在非理想混合过程。此外，对记录的光谱对和分子内O-H伸缩贡献进行小波互相关分析，揭示了向PEG600中添加少量纯EG如何由于分子间连通性的增加而显著影响聚合物基体的结构性质。特别是，在每个记录数据对之间作为重量分数的函数评估的小波互相关参数，在对数线性图中显示，对于约25%重量分数的EG存在一个拐点，这证实了在氢键连接的EG-PEG600分子的三维网络中，EG在确定氢键网络密度增加方面起着关键作用。
