多晶型对纤维素在氢氧化钠/尿素水溶液中溶解的影响。
Effects of polymorphs on dissolution of cellulose in NaOH/urea aqueous solution.
机构信息
MOE Key Laboratory of Wooden Material Science and Application, Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
MOE Key Laboratory of Wooden Material Science and Application, Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
出版信息
Carbohydr Polym. 2015 Jul 10;125:85-91. doi: 10.1016/j.carbpol.2015.02.054. Epub 2015 Mar 6.
This study focused on the effect of cellulose crystal type on the dissolution of cellulose in aqueous NaOH/urea. Cellulose I, II, IIII, and IVI were prepared and characterized. Subsequently, the solubility of these cellulose samples in aqueous NaOH/urea was tested and the mechanism was determined by a combination of (1)H NMR spectroscopy and differential scanning calorimetry (DSC). The results indicated that, compared with the degree of polymerization (DP) and crystallinity index of cellulose, the cellulose crystal type had greater impact on cellulose dissolution. Specially, the solubility of the cellulose I, II, and III was progressively decreased, probably due to different hydrogen bond network and packing energy in it. The ability of cellulose I, II, III, and IV to form hydrogen bonds with sodium hydroxides was nearly the same, while gradually increased when cellulose preparations were associated with urea. Moreover, all the cellulose solutions showed good thermal stability.
本研究集中于纤维素晶型对纤维素在水合氢氧化钠/尿素中溶解的影响。制备并表征了纤维素 I、II、III 和 IV。随后，通过（1）H NMR 光谱和差示扫描量热法（DSC）测试了这些纤维素样品在水合氢氧化钠/尿素中的溶解度，并确定了其溶解机制。结果表明，与纤维素的聚合度（DP）和结晶度指数相比，纤维素晶型对纤维素的溶解有更大的影响。特别是，纤维素 I、II 和 III 的溶解度逐渐降低，可能是由于其氢键网络和堆积能不同所致。纤维素 I、II、III 和 IV 与氢氧化钠形成氢键的能力几乎相同，而与尿素结合时逐渐增加。此外，所有纤维素溶液均表现出良好的热稳定性。
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