Schwan Marina, Rößler Matthias, Milow Barbara, Ratke Lorenz
Institute of Materials Research, German Aerospace Center, Linder Hoehe, 51170 Cologne, Germany.
Gels. 2015 Dec 22;2(1):1. doi: 10.3390/gels2010001.
The production of a new composite material embedding aramid honeycomb materials into nano-porous silica aerogels is studied. Our aim is to improve the poor mechanical strength of silica aerogels by aramid honeycombs without losing the amazing properties of the aerogels like little density and low thermal conductivity. The composite materials were prepared using two formulations of silica aerogels in combination with aramid honeycomb materials of different cell sizes. The silica aerogels are prepared using silicon alkoxides methyltrimethoxysilane and tetraethylorthosilicate as precursors in a two-step acid⁻base sol⁻gel process. Shortly in advance of the gelation point, the aramid honeycombs were fluted by the sol, gelation occurred and, after the aging process, the gel bodies were supercritically dried. The properties of the received composite materials are satisfying. Even the thermal conductivities and the densities are a bit higher than for pure aerogels. Most importantly, the mechanical strength is improved by a factor of 2.3 compared to aramid honeycomb materials and by a factor of 10 compared to the two silica aerogels themselves. The composite materials have a good prospective to be used as an impressive insulation material.
研究了一种将芳纶蜂窝材料嵌入纳米多孔二氧化硅气凝胶中的新型复合材料的制备。我们的目标是通过芳纶蜂窝来改善二氧化硅气凝胶较差的机械强度，同时又不丧失气凝胶诸如低密度和低导热率等惊人特性。使用两种配方的二氧化硅气凝胶与不同孔尺寸的芳纶蜂窝材料相结合制备复合材料。二氧化硅气凝胶采用硅醇盐甲基三甲氧基硅烷和正硅酸四乙酯作为前驱体，通过两步酸碱溶胶 - 凝胶法制备。在凝胶点即将到来之前，芳纶蜂窝被溶胶刻蚀，发生凝胶化，经过老化过程后，凝胶体进行超临界干燥。所得到的复合材料的性能令人满意。甚至其导热率和密度比纯气凝胶略高。最重要的是，与芳纶蜂窝材料相比，机械强度提高了2.3倍，与两种二氧化硅气凝胶本身相比提高了10倍。这些复合材料作为一种令人印象深刻的隔热材料具有良好的应用前景。
