Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States.
Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States.
Nano Lett. 2022 May 25;22(10):3931-3938. doi: 10.1021/acs.nanolett.2c00167. Epub 2022 May 3.
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.
传统的塑料泡沫通常由化石燃料衍生的聚合物制成，这些聚合物在自然界中很难降解。作为替代品，纤维素是一种很有前途的可生物降解聚合物，可用于制造更环保的泡沫，但这种工艺通常依赖于（例如，冷冻干燥和超临界干燥）难以规模化和耗时的方法。在这里，我们通过在含有金属离子的溶液中快速交联纤维素纤维，然后在环境温度下干燥，开发了一种快速且可扩展的方法来制备纤维素-石墨泡沫。所制备的泡沫具有低密度、高强度和优异的耐水性。此外，纤维素纤维的交联可以通过各种金属离子触发，表明其具有良好的通用性。我们进一步使用密度泛函理论揭示了不同离子的交联效应，这与我们的实验观察结果吻合较好。我们的方法为低成本、环保和可扩展的泡沫生产提供了一种可持续的途径，可用于各种应用。
