通过酸碱处理和机械研磨结合的方法制备纳米纤维素(CNFs),并利用冻融循环法分别制备了聚乙烯醇(PVA)和纳米纤维素/聚乙烯醇(CNFs/PVA)复合水凝胶,以及聚乙二醇(PEG)改性PVA和CNFs/PVA复合水凝胶.考察不同配方下复合水凝胶的微观形貌变化,并对复合水凝胶的溶胀性能、压缩强度及热稳定性能进行研究.结果表明,CNFs与PEG对PVA水凝胶的微观形貌均有改善作用,加入PEG后形成的PEG/PVA凝胶产生明显的三维网络结构.当PEG与CNFs同时加入到PVA凝胶后形成的CNFs-PEG/PVA凝胶具有均匀的互穿孔洞结构,此时复合水凝胶的孔隙率最高((67.5±4.3)％),溶胀度最好(980％),且压缩强度较PVA水凝胶也有所提升.PEG对复合凝胶的热稳定性无影响,而加入CNFs后,CNFs-PEG/PVA复合凝胶的初始热分解温度从235℃上升至300℃,显著提高了PVA凝胶的热稳定性.
Cellulose nanofibers (CNFs) were prepared by the combined method of acid alkali treatment and mechanical grinding.Polyvinyl alcohol (PVA),CNFs/PVA,PVA and CNFs/PVA modified by polyethylene glycol (PEG) composite hydrogels were prepared by the freezing/thawing method.The microstructure,swelling property,compressive strength and thermal stability of the PVA composite hydrogels were studied.The results show that the microstructure of PVA hydrogels is perfected by CNFs and PEG.After adding PEG,PEG/PVA composite hydrogel has obvious 3D network.When both PEG and CNFs are added into the PVA hydrogel,the obtained CNFs-PEG/ PVA hydrogel forms a uniform network structure.The porosity and swelling degree of the CNFs-PEG/PVA hydrogel reach up to (67.5 ± 4.3)％ and 980％,respectively.Compared with the pure PVA hydrogel,the compressive strength of CNFs-PEG/PVA hydrogel also increases.The addition of PEG has no effect on the thermal stability of the PVA hydrogel,but the addition of CNFs significantly improves the thermal stability of CNFs-PEG/ PVA hydrogel,and the initial thermal decomposition temperature of CNFs-PEG/PVA composite hydrogel increases from 235 ℃ to 300 ℃.
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