Institute of New Bamboo and Rattan Based Biomaterials, International Center for Bamboo and Rattan, Beijing, 100102, PR China; Faculty of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S3B3, Canada.
Institute of New Bamboo and Rattan Based Biomaterials, International Center for Bamboo and Rattan, Beijing, 100102, PR China; SFA and Beijing Co-built Key Lab for Bamboo and Rattan Science & Technology, Beijing, 100102, PR China.
Carbohydr Polym. 2019 Mar 15;208:232-240. doi: 10.1016/j.carbpol.2018.12.073. Epub 2018 Dec 22.
Cellulose aerogels have shown outstanding potential as renewable functional materials; however, their practical applications are still limited by inherent hydrophilicity and weak mechanical properties. To overcome hydrophilicity and fragility issues of aerogels, in this study, silylated bamboo-derived cellulose nanofibrils (CNF) aerogels with aligned porous structures were achieved by directionally freeze-casting a mixture of CNF suspension and methyltrimethoxysilane sol. The silylated CNF aerogels exhibited distinct aligned lamellar structures and significantly anisotropic mechanical properties. They had improved strength and stiffness in the axial direction (along the freezing direction) and excellent rapid shape recovery ability in the radial direction (perpendicular to the freezing direction) with a significant high shape recovery ratio of 92% after 100 cycles at 80% compression. Owing to their ultra-low density, hydrophobicity, and high compressive recoverability, the silylated CNF aerogels can be potentially used in a wide range of industrial applications, such as hydrophobic polymer nanocomposites, absorbents, and biomedical scaffolds.
纤维素气凝胶作为可再生的功能性材料具有突出的潜力；然而，由于其固有的亲水性和较弱的机械性能，其实际应用仍然受到限制。为了克服气凝胶的亲水性和脆性问题，本研究通过定向冷冻铸造纤维素纳米纤维（CNF）悬浮液和甲基三甲氧基硅烷溶胶的混合物，制备了具有取向多孔结构的硅烷化竹衍生纤维素纳米纤维气凝胶。硅烷化 CNF 气凝胶表现出明显的取向层状结构和显著各向异性的机械性能。它们在轴向（沿冷冻方向）具有增强的强度和刚性，在径向（垂直于冷冻方向）具有优异的快速形状恢复能力，在 80%压缩下经过 100 次循环后，形状恢复率高达 92%。由于其超低密度、疏水性和高压缩可恢复性，硅烷化 CNF 气凝胶有望在各种工业应用中得到应用，如疏水性聚合物纳米复合材料、吸收剂和生物医学支架。
