College of Polymer Science and Engineering, China.
College of Arts Sichuan University, China.
Carbohydr Polym. 2017 Aug 1;169:92-100. doi: 10.1016/j.carbpol.2017.02.089. Epub 2017 Mar 21.
The enzymatic degradation behavior of hydroxyethyl cellulose (HEC) samples with different molar substitutions (MS) values was investigated. The changes in the molecular structure of HEC treated with enzymatic approach in comparison to the native HEC were studied through nuclear magnetic resonance (NMR), fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques and kinetics of degradation was studied by viscometry. The cleavage of HEC chains could be observed from FTIR and kinetics results. Moreover, reduce in molecular weight (Mw) of polymer and liberated glucose concentration was investigated by gel permeation chromatography (GPC) analysis during enzymatic degradation. And all these results indicated that HEC with lower MS is more susceptible to degrade and provided a better understanding of the mechanism operating during enzymatic hydrolysis of HEC by cellulases. Furthermore, by complete degradation and quantification of liberated glucose, the substitution index (SI) and the distribution of substituents along the HEC chain were investigated. The results suggested that the HEC samples differed in hydroxyethyl molar substitutions (MS) and possible distribution of the hydroxyethyl groups. Impressively, our efforts established a facile analytical method for the elucidation of the distribution of substituents along the HEC chain.
研究了不同摩尔取代度（MS）的羟乙基纤维素（HEC）样品的酶降解行为。通过核磁共振（NMR）、傅里叶变换红外光谱（FTIR）、X 射线衍射（XRD）和扫描电子显微镜（SEM）技术研究了用酶法处理的 HEC 与天然 HEC 的分子结构变化，并通过粘度法研究了降解动力学。可以从 FTIR 和动力学结果中观察到 HEC 链的断裂。此外，通过凝胶渗透色谱（GPC）分析，在酶降解过程中研究了聚合物分子量（Mw）的降低和释放的葡萄糖浓度。所有这些结果表明，MS 较低的 HEC 更容易降解，并为纤维素酶水解 HEC 过程中的机制提供了更好的理解。此外，通过完全降解和释放葡萄糖的定量，可以研究取代基指数（SI）和取代基在 HEC 链上的分布。结果表明，HEC 样品在羟乙基摩尔取代度（MS）和羟乙基基团的可能分布上存在差异。令人印象深刻的是，我们的努力为阐明 HEC 链上取代基的分布建立了一种简便的分析方法。
