Key Lab of Science and Technology of Eco-textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People's Republic of China; Innovation Center for Textile Science and Technology of Donghua University, Donghua University, Shanghai 201620, People's Republic of China.
Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, United States of America.
Int J Biol Macromol. 2020 Apr 1;148:811-816. doi: 10.1016/j.ijbiomac.2020.01.172. Epub 2020 Jan 18.
Cellulosic colloidal suspensions present unique opportunities for rheological modification of complex fluids. In this work, the rheological behavior of regenerated cellulose (RC) suspensions, including their oscillating shear and time-dependent behavior, as well as yield stress, were studied. The rheological effects of sodium alginate's addition to aqueous RC solutions subject to shear flow were investigated. The results reveal that the RC suspension exhibited "gel-like" behavior and had a shear-thinning property. At increasing RC concentrations, the suspensions' yield stress and the extent of viscosity recovery after plastic deformation had both increased. The viscoelastic suspensions underwent a transition from "solid-like" to "liquid-like" behavior upon sodium alginate's inclusion. Sodium alginate was found to enhance RC suspensions' viscosity recoverability. Furthermore, with increasing concentrations of sodium alginate, the yield stress of RC suspension began to decrease and then vanished, occurring below the 1:1 RC: sodium alginate weight ratio with total solid content fixed at 1 wt%, due to RC's inability to form an extended network RC. This study yields insights into the rheology of RC suspensions and the influence of sodium alginate and supports both their usage as rheological modifies in applications such as coatings, drug delivery systems, and additive manufacturing techniques such as 3D printing.
纤维素胶体悬浮液为复杂流体的流变改性提供了独特的机会。在这项工作中，研究了再生纤维素 (RC) 悬浮液的流变行为，包括其振荡剪切和时变行为以及屈服应力。研究了在剪切流作用下向 RC 水溶液中添加海藻酸钠对其流变性能的影响。结果表明，RC 悬浮液表现出“凝胶状”行为，并具有剪切变稀特性。随着 RC 浓度的增加，悬浮液的屈服应力和塑性变形后粘度恢复程度都有所增加。粘弹性悬浮液在添加海藻酸钠后从“固态”转变为“液态”行为。发现海藻酸钠可以提高 RC 悬浮液的粘度恢复能力。此外，随着海藻酸钠浓度的增加，RC 悬浮液的屈服应力开始下降，然后消失，在总固含量为 1 wt% 且固定的情况下，当 RC:海藻酸钠的重量比达到 1:1 时，这是由于 RC 无法形成延伸的网络 RC。该研究深入了解了 RC 悬浮液的流变特性以及海藻酸钠的影响，并支持它们在涂料、药物输送系统和添加剂制造技术（如 3D 打印）等应用中作为流变改性剂的使用。
