Abstract：
Forests are a major source of wealth for Canadians, and cellulose makes up the \"skeleton\" of wood fibers. Concentrated H2SO4 and NaOH/urea aqueous solutions are two efficient solvents that can rapidly dissolve cellulose. Our preliminary experiment obtained regenerated wood cellulose films with different mechanical properties from these two solvents. Therefore, herein, we aim to investigate the effects of aqueous solvents on the structure and properties of wood cellulose films. Regenerated cellulose (RC) films were produced by dissolving wood cellulose in either 64 wt% H2SO4 solution (RC-H4) or NaOH/urea aqueous solution (RC-N4). RC-H4 showed the higher tensile strength (109.78 ± 2.14 MPa), better folding endurance (20-28 times), and higher torsion angle (42°) than RC-N4 (62.90 ± 2.27 MPa, un-foldable, and 12°). The increased cellulose contents in the H2SO4 solutions from 3 to 5 wt% resulted in an improved tensile strength from 102.61 ± 1.99 to 132.93 ± 5.64 MPa and did not affect the foldability. RC-H4 also exhibited better water vapor barrier property (1.52 ± 0.04 × 10-7 g m-1 h-1 Pa-1), superior transparency (~90 % transmittance at 800 nm), but lower thermal stability compared to RC-N4. This work provides special insights into the regenerated wood cellulose from two aqueous solvents and is expected to facilitate the development of high-performance RC films from abundant forestry resources.
摘要：
森林是加拿大人的主要财富来源，纤维素构成了木纤维的“骨架”。浓H2SO4和NaOH/尿素水溶液是两种可以快速溶解纤维素的有效溶剂。我们的初步实验从这两种溶剂中获得了具有不同机械性能的再生木质纤维素膜。因此,在这里，我们旨在研究水性溶剂对木质纤维素薄膜结构和性能的影响。通过将木质纤维素溶解在64重量%H2SO4溶液(RC-H4)或NaOH/尿素水溶液(RC-N4)中来制备再生纤维素(RC)膜。RC-H4具有较高的抗拉强度（109.78±2.14MPa），更好的折叠耐久性（20-28倍），扭转角(42°)高于RC-N4(62.90±2.27MPa,不可折叠，和12°）。H2SO4溶液中的纤维素含量从3wt％增加到5wt％，导致拉伸强度从102.61±1.99提高到132.93±5.64MPa，并且不影响可折叠性。RC-H4还表现出更好的水蒸气阻隔性能（1.52±0.04×10-7g-1h-1Pa-1），优异的透明度（〜90％的透射率在800纳米），但热稳定性低于RC-N4。这项工作提供了对两种水性溶剂中再生木材纤维素的特殊见解，并有望促进从丰富的林业资源中开发高性能RC膜。
