Exploring the diffusion behavior of urea aqueous solution in the viscose film by ATR-FTIR spectroscopy
Exploring the diffusion behavior of urea aqueous solution in the viscose film by ATR-FTIR spectroscopy
复制标题
利用 ATR-FTIR 光谱探讨尿素水溶液在粘胶膜中的扩散行为
DOI：
10.1007/s10570-020-02997-y
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发表时间：
2020-03-01
期刊：
影响因子：
5.7
通讯作者：
Wu, Peiyi
中科院分区：
文献类型：
--
作者：
Dong, Yan;Hou, Lei;Wu, Peiyi
摘要用时间分辨衰减全反射傅里叶变换红外光谱结合微扰相关移动窗技术研究了尿素水溶液在粘胶薄膜中的扩散机理。在整个扩散过程中可以观察到两个阶段：(1)水从尿素水溶液扩散到粘胶膜中；(2)尿素和水同时通过粘胶膜扩散。此外，尿素在粘胶薄膜中的扩散曲线符合Fickian扩散模型，并可据此计算扩散系数。结果表明，尿素的扩散速率随浓度的增加而略有下降。此外，考虑到纤维素的C-O伸缩振动(主要是-CH2-O(6)H基)引起的谱带频移，认为水分子是与纤维素相互作用的主要成分，首先破坏无定形区的天然氢键网络，然后在扩散过程中建立新的纤维素-水氢键。另一方面，尿素分子只是通过固定水分子并在粘胶薄膜中形成尿素-水缔合作用来降低水溶液的扩散迁移率。因此，推测尿素分子在扩散过程中通过影响水分子的流动性而不是直接与粘胶薄膜中的纤维素链相互作用而起到间接作用。研究结果可为尿素在活性染料印花和纤维素溶解方面的应用提供指导。
AbstractThe diffusion mechanism of the urea aqueous solution in the viscose film is investigated by time-resolved attenuated total reflectance-Fourier transform infrared spectroscopy combining with perturbation correlation moving window technique. Two stages can be observed during the whole diffusion process: (1) water diffuses from urea aqueous solution into the viscose film, (2) urea and water diffuse simultaneously through the viscose film. Additionally, the diffusion curve of urea in the viscose film fits Fickian diffusion model, and the diffusion coefficients can be calculated accordingly. It is shown that the diffusion rate of urea slightly decreases with increasing concentration. Furthermore, considering the frequency shift of bands attributed to C–O stretching vibration (mainly –CH2–O(6)H groups) of cellulose, it is suggested that water molecules are the dominant component interacting with cellulose by first breaking the native hydrogen-bonding network in the amorphous region and then building new cellulose-water hydrogen bonds during the diffusion process. On the other hand, urea molecules merely decrease the diffusion mobility of aqueous solutions by immobilizing the water molecules and forming urea-water associations in the viscose film. Thus, it is inferred that urea molecules play an indirect role by influencing the mobility of water molecules rather than directly interacting with cellulose chain in the viscose film during diffusion. The results herein could provide guidance in the filed of urea’s function in reactive dye printing and cellulose dissolution.Graphic abstract