目的 制备具有抗菌、抗氧化性能的物理化学双交联水凝胶包装材料,研究纳米纤维素及单宁酸对水凝胶性能的影响.方法 以纳米纤维素(CNF)、单宁酸(TA)、丙烯酸(AA)和丙烯酰胺(AM)为原料,通过"一锅法"制备具有物理和化学双交联结构的功能性纳米纤维素水凝胶,研究水凝胶的力学性能、保水性、抗氧化性、抗菌性和缓释性能.结果 AA 和 AM 在交联剂的作用下发生自由基共聚形成聚(丙烯酸-丙烯酰胺)(P(AA-AM))共聚物,构成三维交联网络体系,聚合物分子链与CNF和TA又通过氢键作用形成物理交联网络,双交联网络使水凝胶的保水性提高;加入 CNF后,在 85%压缩应变下,水凝胶的压缩强度提升了 83.7%;所制备的水凝胶具有优异的抗菌性能,且对革兰氏阳性菌的抑制性较优;水凝胶中的TA能够在 70 h内逐渐释放到缓冲溶液中,表现出较好的缓释性能.结论 通过构建双交联网络形成的水凝胶具有较好的保水性及抗菌、抗氧化性,有望在食品包装领域得到广泛应用.
Preparation and Properties of Functional Nanocellulose-based Hydrogels
The work aims to prepare a physico-chemical double-crosslinked hydrogel packaging material with antibacterial and antioxidant properties and study the effects of nanocellulose and tannic acid on hydrogel properties.With nanocellulose(CNF),tannic acid(TA),acrylic acid(AA)and acrylamide(AM)as raw materials,the functional nanocellulose-based hydrogel with physico-chemical double-crosslinked structure was prepared by"one-pot method",and the mechanical properties,water retention,oxidation resistance,antibacterial property and slow-release properties of the hydrogel were studied.The free radical copolymerization crosslinking reaction occurred between acrylamide and acrylic acid under the action of crosslinking agent,and the chains entangled with each other to form a three-dimensional crosslinked network.The hydrogen bonds between the copolymer molecular chains,CNF and TA facilitated the formation of the second physical crosslinked network,enhancing the water retention of the hydrogel.After the incorporation of nanocellulose,the compressive strength of the hydrogel increased by 83.7%at 85%strain.After the incorporation of TA,the hydrogel exhibited excellent antibacterial properties,with superior inhibitory effects on Gram-positive bacteria.Moreover,the tannic acid in the modified hydrogel could be gradually released from the hydrogel within 70 h,showing a good slow-release property.The hydrogel formed by constructing double crosslinked networks exhibits excellent water retention,antibacterial,and antioxidant properties,suggesting their potential for widespread application in food packaging.
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