Wet stable and mechanically robust cellulose nanofibrils (CNF) based hydrogel
Wet stable and mechanically robust cellulose nanofibrils (CNF) based hydrogel
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DOI：
10.1016/j.polymer.2018.07.016
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发表时间：
2018-08-29
期刊：
影响因子：
4.6
通讯作者：
Mason, Michael D.
中科院分区：
文献类型：
--
作者：
Hossen, Muhammad R.;Dadoo, Nayereh;Mason, Michael D.
由纤维素纳米原纤维（CNF）水凝胶制成的冷冻干燥的高度多孔材料能够在其3D结构内吸收和储存大量的液体，总吸收能力随孔隙率线性增加。冷冻干燥的高孔隙率CNF凝胶的挑战之一是它们在水性环境中快速分解的倾向。在这里，我们探索了一种方法，以克服这一缺陷，将甲基丙烯酸酯官能化的羧甲基纤维素（MetCMC）的CNF系统，然后通过紫外线照射，导致甲基丙烯酸酯基团的MetCMC交联。所得的聚合物复合材料基质成功地保持了坚固的3D结构，即使在重新润湿并储存在水中时也不会塌陷。当冷冻干燥时，CNF-MetCMC复合材料保持其尺寸和形状，而空气干燥引起显著的收缩。相比之下，空气干燥的CNF-MetCMC水凝胶在再润湿时溶胀。通过控制复合材料中CNF和MetCMC之间的比例来调节CNF-MetCMC水凝胶的溶胀和收缩。MetCMC的甲基丙烯酸酯基团之间的交联也显著增强CNF-MetCMC凝胶的干模量和湿模量。我们调用一个简单的模型，涉及氢键和交联之间的平衡来解释这些数据。(C)2018爱思唯尔有限公司版权所有
Freeze dried, highly porous materials made from cellulose nanofibrils (CNF) hydrogels are capable of absorbing and storing a significant quantity of liquid inside their 3D structure, with total absorption capacity increasing linearly with porosity. One of the challenges of freeze dried high porosity CNF gels is their propensity to break down rapidly in aqueous environments. Here we explore a method to overcome this deficiency by incorporating methacrylate functionalized carboxymethyl cellulose (MetCMC) into the CNF system followed by UV irradiation leading to crosslinking of the methacrylate groups of MetCMC. The resultant polymer composite matrix successfully maintains a robust 3D structure, without collapsing, even when rewetted and stored in water. When freeze dried, the CNF-MetCMC composite maintains its size and shape whereas air drying induces significant shrinkage. In contrast, air dried CNF-MetCMC hydrogels swell when rewetted. Swelling and shrinkage of CNF-MetCMC hydrogels were tuned by controlling the ratio between CNF and MetCMC in the composite. The crosslinking between the methacrylate groups of MetCMC also enhances the dry and wet modulus of CNF-MetCMC gels significantly. We invoke a simple model involving a balance between hydrogen bonding and crosslinking to explain these data. (C) 2018 Elsevier Ltd. All rights reserved.