University of Chinese Academy of Sciences, Beijing 100039, China.
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Biomacromolecules. 2022 Jun 13;23(6):2264-2271. doi: 10.1021/acs.biomac.1c01553. Epub 2022 Mar 24.
With the emergence of efficient green solvents, structural regulation of regenerated cellulose is highly desired in the solution process from an industrial perspective. Cellulose fiber and films are viewed as a "composite" comprising amorphous and crystalline fractions. The regulation of the crystalline structure is of great importance for the properties of cellulose materials. In this study, we found stretch-induced crystallization behavior during the transition from solution to gel via coagulation. The crystallinity index of the hydrogel fiber increases with the stretch ratio (SR). X-ray diffraction revealed that the cellulose II hydrate formed in the stretched hydrogel fibers. The mechanical properties and thermal stability of the dry fibers greatly improved against the SR. This crystallization behavior depends on the concentration of the solution and the type of ionic liquid. This stretch-induced crystallization provides an efficient method for structural regulation in cellulose solution processing.
随着高效绿色溶剂的出现，从工业角度来看，再生纤维素在溶液加工中的结构调控备受期待。纤维素纤维和薄膜被视为一种“复合材料”，由无定形和结晶两部分组成。结晶结构的调控对于纤维素材料的性能非常重要。在这项研究中，我们发现了在通过凝固从溶液向凝胶转变的过程中，拉伸诱导结晶的行为。水凝胶纤维的结晶度指数随拉伸比（SR）的增加而增加。X 射线衍射表明，纤维素 II 水合物在拉伸水凝胶纤维中形成。干燥纤维的机械性能和热稳定性随着 SR 的增加而大大提高。这种结晶行为取决于溶液的浓度和离子液体的类型。这种拉伸诱导结晶为纤维素溶液加工中的结构调控提供了一种有效的方法。
