Feng Yuwei, Chang Yuqing, Wang Li, Liu Xiaodi, Chen Lei, Yan Xiaofei, Zhang Qiang
Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai 200241, PR China.
College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou, 310018, PR China.
Carbohydr Polym. 2025 Jan 1;347:122671. doi: 10.1016/j.carbpol.2024.122671. Epub 2024 Aug 31.
Ultrahigh-strength and lightweight materials have found wide use. However, it is difficult for artificial materials to maintain high strength while being lightweight, as the mechanical properties of most materials are strongly dependent on density. In this study, we combined the methods of freeze casting and solvent exchange to prepare cellulose nanofiber foams with lightweight and ultrahigh strength. Freeze casting created the continuous 3D network at the microscale while solvent exchange promoted the reconstruction of cellulose nanofibers via the alkali-induced mercerization effect. The foams thus possessed an ordered hierarchical structure that contained lamellar layers at the microscale and a high density of pores at the nanoscale. A quadratic exponential positive correlation between relative modulus and relative density was identified for the foams. The maximum compressive and bending moduli of the foams were 26.09 and 42.10 MPa, respectively, while its density was 210.16 mg/cm. The study provides a robust method for the preparation of lightweight and high-strength cellulose foams.
超高强度和轻质材料已得到广泛应用。然而，人工材料很难在保持轻质的同时维持高强度，因为大多数材料的机械性能强烈依赖于密度。在本研究中，我们结合冷冻铸造和溶剂交换方法制备了具有轻质和超高强度的纤维素纳米纤维泡沫材料。冷冻铸造在微观尺度上创建了连续的三维网络，而溶剂交换通过碱诱导丝光化效应促进了纤维素纳米纤维的重构。这些泡沫材料因此具有有序的分级结构，在微观尺度上包含层状结构，在纳米尺度上具有高密度的孔隙。研究发现这些泡沫材料的相对模量和相对密度之间存在二次指数正相关关系。这些泡沫材料的最大压缩模量和弯曲模量分别为26.09和42.10兆帕，而其密度为210.16毫克/立方厘米。该研究为制备轻质高强度纤维素泡沫材料提供了一种可靠的方法。
