Lu Peng, Liu Ren, Liu Xin, Wu Min
Institute of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning 530004, China.
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.
Nanomaterials (Basel). 2018 Oct 8;8(10):800. doi: 10.3390/nano8100800.
Cellulose hydrogels are often prepared from native cellulose through a direct cellulose dissolution approach that often involves tedious process and solvent recovery problems. A self-supporting cellulose hydrogel was prepared by gelation of the TEMPO-oxidized bagasse cellulose nanofibrils (CNF) triggered by strong crosslinking between carboxylate groups and Zn. TEMPO process was used to generate negatively charged carboxylate groups on CNF surface to provide a high binding capability to Zn. Three TEMPO-oxidized CNFs of different carboxylate contents were prepared and characterized. TEM and AFM microscopes suggested that the sizes of CNFs were fined down and carboxylated cellulose nanofibrils (TOCNFs) of 5⁻10 nm wide, 200⁻500 nm long, and carboxylate contents 0.73⁻1.29 mmol/g were obtained. The final structures and compressive strength of hydrogels were primarily influenced by interfibril Zn-carboxylate interactions, following the order of TOCNFs concentration > content of carboxylate groups > concentration of zinc ions. A CO₂ sensitive self-supporting cellulose hydrogel was developed as a colorimetric indicator of food spoilage for intelligent food packaging applications.
纤维素水凝胶通常通过直接纤维素溶解方法由天然纤维素制备，该方法常常涉及繁琐的过程和溶剂回收问题。通过由羧酸盐基团与锌之间的强交联引发的TEMPO氧化甘蔗渣纤维素纳米原纤（CNF）的凝胶化制备了一种自支撑纤维素水凝胶。TEMPO工艺用于在CNF表面产生带负电荷的羧酸盐基团，以提供对锌的高结合能力。制备并表征了三种不同羧酸盐含量的TEMPO氧化CNF。透射电子显微镜（TEM）和原子力显微镜（AFM）表明CNF的尺寸细化，得到了宽度为5-10nm、长度为200-500nm且羧酸盐含量为0.73-1.29mmol/g的羧化纤维素纳米原纤（TOCNF）。水凝胶的最终结构和抗压强度主要受原纤间锌-羧酸盐相互作用的影响，顺序为TOCNF浓度>羧酸盐基团含量>锌离子浓度。开发了一种对CO₂敏感的自支撑纤维素水凝胶作为用于智能食品包装应用的食品腐败比色指示剂。
