Wu Kede, Cao Junxiang, Qian Zhen, Luo Yi, Niu Bo, Zhang Yayun, Long Donghui
Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, School of Chemical Engineering, Shanghai 200237, PR China.
Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, School of Chemical Engineering, Shanghai 200237, PR China.
J Colloid Interface Sci. 2022 Jul 15;618:259-269. doi: 10.1016/j.jcis.2022.03.087. Epub 2022 Mar 23.
Carbon aerogels exhibit high porosity, good electrical conductivity, and low thermal conductivity, but their practical applications are greatly hindered by their tedious preparation and inherent structure brittleness. Herein, monolithic carbon aerogels (MCAs) with low density and large size are prepared via a facile sol-gel polymerization of phenolic resin within melamine foam (MF), followed by ambient pressure drying and co-carbonization. During ambient pressure drying process, the MF matrix can deliver supporting force to counteract against the solvent evaporation surface tension, thus inhibiting volume shrinkage and shape deformation. Upon co-carbonization process, the MF matrix and organic aerogel could pyrolyze and shrink cooperatively, which could effectively prevent the brittle fracture of monolith. Therefore, large-sized MCAs (up to 250 × 250 × 20 mm) with low densities of 0.12-0.22 g·cm are obtained. The as-obtained MCAs possess high compressive strength (2.50 MPa), ultra-low thermal conductivity (0.051 W·m·K at 25 °C and 0.111 W·m·K at 800 °C), and high-volume organic absorption capability (77.3-88.0%, V/V). This facile and low-cost method for the fabrication of large-sized monolithic carbon aerogels with excellent properties could envision enormous potential for high-temperature thermal insulation and organics absorption.
碳气凝胶具有高孔隙率、良好的导电性和低导热性，但其繁琐的制备过程和固有的结构脆性极大地阻碍了它们的实际应用。在此，通过在三聚氰胺泡沫（MF）中对酚醛树脂进行简便的溶胶-凝胶聚合，随后进行常压干燥和共碳化，制备出了低密度、大尺寸的整体式碳气凝胶（MCA）。在常压干燥过程中，MF基体能够提供支撑力以抵消溶剂蒸发表面张力，从而抑制体积收缩和形状变形。在共碳化过程中，MF基体和有机气凝胶可以协同热解和收缩，这能够有效地防止整体材料发生脆性断裂。因此，获得了尺寸高达250×250×20mm、密度为0.12 - 0.22g·cm的大尺寸MCA。所制备的MCA具有高抗压强度（2.50MPa）、超低导热性（25℃时为0.051W·m·K，800℃时为0.111W·m·K）以及高体积有机物吸收能力（77.3 - 88.0%，V/V）。这种制备具有优异性能的大尺寸整体式碳气凝胶的简便且低成本的方法，在高温隔热和有机物吸收方面具有巨大的潜力。
