Fabrication of Cellulose–Graphite Foam via Ion Cross-linking and Ambient-Drying
Ruiliu Wang, Chaoji Chen, Zhenqian Pang, Xizheng Wang, Yubing Zhou, Qi Dong, Miao Guo, Jinlong Gao, Upamanyu Ray, Qinqin Xia, Zhiwei Lin, Shuaiming He, Bob Foster, Teng Li, Liangbing Hu
Abstract
Conventional plastic foams are usually produced by fossil-fuel-derived polymers, which are difficult to degrade in nature. As an alternative, cellulose is a promising biodegradable polymer that can be used to fabricate greener foams, yet such a process typically relies on methods (e.g., freeze-drying and supercritical-drying) that are hardly scalable and time-consuming. Here, we develop a fast and scalable approach to prepare cellulose-graphite foams via rapidly cross-linking the cellulose fibrils in metal ions-containing solution followed by ambient drying. The prepared foams exhibit low density, high compressive strength, and excellent water stability. Moreover, the cross-linking of the cellulose fibrils can be triggered by various metal ions, indicating good universality. We further use density functional theory to reveal the cross-linking effect of different ions, which shows good agreement with our experimental observation. Our approach presents a sustainable route toward low-cost, environmentally friendly, and scalable foam production for a range of applications.