The preparation and characterization of chemically deuterium incorporated cotton fibers
The preparation and characterization of chemically deuterium incorporated cotton fibers
复制标题
化学掺氘棉纤维的制备及表征
DOI：
10.1007/s10570-021-03869-9
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发表时间：
2021-04-23
期刊：
影响因子：
5.7
通讯作者：
Ragauskas, Arthur J.
中科院分区：
文献类型：
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作者：
Song, Yan;Jiang, Wei;Ragauskas, Arthur J.
掺氢纤维素的制备是研究纤维素内部结构、拓展纤维素材料应用领域的重要工具。在本研究中，通过化学氢-氢交换处理，在纤维素中加入了抗再水合(抗交换)氢的纤维素棉纤维。用核磁共振氢谱(1H-核磁共振)表征了氢-氢交换过程随交换时间的变化。用傅里叶变换红外光谱(FTIR)和稳定同位素比质谱仪(IRSM)测定了反再水合反应中的氚掺入量。探讨了氢取代对棉纤维的光谱数据、微观结构、结晶信息、聚合度以及热重分析(炭化和燃烧)的影响。对化学交换过程的分析表明，在最初的几分钟内，氢-氚交换优先发生在无定形纤维组分中。反再水化结晶阶段的氢交换需要几个小时。随着处理时间的延长，棉纤维的抗交换能力增强，最高可达纤维羟基的60%。红外光谱、傅里叶变换拉曼光谱和近红外光谱的表征都显示出纤维素羟基上的氚光谱同位素效应。而除了反应温度的影响外，掺氢同位素效应并不影响纤维素的微观结构、结晶指数和聚合度。此外，由于热力学同位素效应，氢化棉纤维在氮气和空气气氛下的热重分析都发生了变化。这些观察揭示了氢-氚交换处理过程及其对纤维素纤维性能的影响，这有助于我们更好地了解纤维素的内部结构，并可能促进氢化纤维素材料的潜在利用。
Preparation of deuterium incorporated cellulose is a vital tool to investigate cellulose internal structure and to expand the application fields of cellulose materials. In this study, cellulosic cotton fibers with anti-rehydration (exchange-resistant) deuterium incorporated in cellulose were prepared by chemical hydrogen–deuterium exchange treatment. The chemical hydrogen–deuterium exchange process, along with exchange time, were characterized by nuclear magnetic resonance hydrogen spectroscopy (1H-NMR). The anti-rehydration deuterium incorporation was determined by Fourier Transform infrared spectroscopy (FTIR) and Stable Isotope Ratio Mass Spectrometer (IRSM). The effect of the deuterium hydroxyl substitution on cotton fiber’s spectral data, microstructure, crystalline information, degree of polymerization, as well as it’s thermogravimetric analysis (charcoalization and combustion) are explored. Analysis of the chemical exchange process indicated that the hydrogen–deuterium exchange occurred preferentially in the amorphous cellulose component over the first several minutes. Deuterium exchange in the anti-rehydration crystalline phase took several hours. Increasing the treatment time, enhanced exchange-resistant deuterium incorporation to as high as about 60% of the cotton fibers’ cellulose hydroxyl groups was achieved. The characterization of FTIR, Fourier transform Raman (FT-Raman), and near-infrared spectra (NIR) all exhibited the deuterium spectral isotope effect on cellulose hydroxl groups. While, apart from the effect of reaction temperature, deuterium incorporation isotope effect did not affect the cellulose microstructure, crystalline index and the degree of polymerization properties. Furthermore, the thermogravimetric analysis of deuterated cotton fibers under N2and air atmosphere were both altered due to the thermodynamic isotope effect. These observations revealed the hydrogen–deuterium exchange treatment process and impacts on cellulose fiber properties, which helped us to better understand the cellulose internal structure and may facilitate the potential utilization of deuterated cellulosic materials.