Abstract Clay aerogels have many attractive properties, such as low thermal conductivities, good thermal stabilities and low flammability. But the generally weak mechanical property severely restrains their practical applications. Incorporation of polymers into clay aerogel could achieve desirable strength, unfortunately, the fire resistance or insulating properties were sacrificed to some extent. In this work, fire-resistant palygorskite/wood fiber composite aerogels with low densities were prepared by an eco-friend freeze-drying method. In the aerogels, palygorskite contents were up to 80 wt% while only a small amount of wood fiber were used as reinforced filler. The composite aerogel had an array of porous structure with intertwined palygorskite fibers as pore walls, which resulted in a low thermal conductivity of 0.033 W/mK. In addition, the composite aerogel exhibited good mechanical strength with the Young's modulus up to 4.7 MPa while the density was lower than 0.08 g/cm3. Overall, an outstanding combination of excellent machinability, thermal stability, high limiting oxygen index, and prominent flame-retardant properties has been achieved in the composite aerogels. This work represents a significant progress of porous materials development and makes the practical applications of clay-based aerogel insulators realistic.

中文翻译：

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优异的阻燃和隔热坡缕石/木纤维复合气凝胶，具有改进的机械性能

摘要 粘土气凝胶具有许多吸引人的特性，如低热导率、良好的热稳定性和低可燃性。但普遍较弱的力​​学性能严重制约了它们的实际应用。将聚合物掺入粘土气凝胶可以达到理想的强度，不幸的是，在一定程度上牺牲了耐火性或绝缘性能。在这项工作中，通过生态友好的冷冻干燥方法制备了低密度的耐火坡缕石/木纤维复合气凝胶。在气凝胶中，坡缕石含量高达 80 wt%，而仅使用少量木纤维作为增强填料。该复合气凝胶具有一系列多孔结构，以交织的坡缕石纤维作为孔壁，导热系数低至 0.033 W/mK。此外，复合气凝胶表现出良好的机械强度，杨氏模量高达4.7 MPa，而密度低于0.08 g/cm3。总体而言，复合气凝胶实现了优异的可加工性、热稳定性、高极限氧指数和突出的阻燃性能的完美结合。这项工作代表了多孔材料开发的重大进展，并使粘土基气凝胶绝缘体的实际应用成为现实。