Dissolution and regeneration of cellulose in NaOH/thiourea aqueous solution
Dissolution and regeneration of cellulose in NaOH/thiourea aqueous solution
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DOI：
10.1002/polb.10215
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发表时间：
2002-07
期刊：
影响因子：
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通讯作者：
Lina Zhang;Dong Ruan;Gao Shanjun
中科院分区：
文献类型：
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作者：
Lina Zhang;Dong Ruan;Gao Shanjun
用一种新型的纤维素溶剂1.5M NaOH/0.65M硫脲水溶液溶解分子量为10.1 × 104的棉短绒，制备纤维素溶液。再生纤维素（RC）膜通过用浓度为2至30重量%的硫酸（H2SO 4）水溶液浸渍而从纤维素溶液获得。通过红外光谱、X射线衍射、扫描电镜、13 C NMR和拉伸试验研究了纤维素的溶解性、RC膜的结构和力学性能。~（13）C NMR分析表明，纤维素的新溶剂是一种非衍生物水溶液体系。硫脲的存在显著提高了纤维素在NaOH水溶液中的溶解度，减少了纤维素凝胶的形成，阻碍了纤维素分子间的缔合，导致纤维素的溶剂化。结果表明，用质量分数为5%的H2SO 4水溶液浸泡5 min，所得RC膜具有较高的力学性能和均匀的多孔结构，湿态下自由表面平均孔径为186 nm。用10%甘油增塑5 min后，RC膜的拉伸强度为107 MPa，断裂伸长率为10%，其中1%左右的甘油对RC膜的力学性能有重要的提高作用。© 2002 Wiley Periodicals，Inc.聚合物科学杂志B部分：聚合物物理40：1521-1529，2002
A novel cellulose solvent, 1.5 M NaOH/0.65 M thiourea aqueous solution, was used to dissolve cotton linters having a molecular weight of 10.1 × 104 to prepare cellulose solution. Regenerated cellulose (RC) films were obtained from the cellulose solution by coagulating with sulfuric acid (H2SO4) aqueous solution with a concentration from 2 to 30 wt %. Solubility of cellulose, structure, and mechanical properties of the RC films were examined by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, 13C NMR, and tensile tests. 13C NMR analysis indicated that the novel solvent of cellulose is a nonderivative aqueous solution system. The presence of thiourea enhanced significantly the solubility of cellulose in NaOH aqueous solution and reduced the formation of cellulose gel; as a result, thiourea prevented the association between cellulose molecules, leading to the solvation of cellulose. The RC film obtained by coagulating with 5 wt % H2SO4 aqueous solution for 5 min exhibited higher mechanical properties than that with other H2SO4 concentrations and a homogenous porous structure with a mean pore size of 186 nm for free surface in the wet state. The RC film plasticized with 10% glycerin for 5 min had a tensile strength of 107 MPa and breaking elongation of 10%, and about 1% glycerin in the RC film plays an important role in the enhancement of the mechanical properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1521–1529, 2002