PDF(Pubmed)
Abstract：
Aromatic polyisocyanurate (PIR) aerogels are recognized as advanced porous materials and extensively studied due to their lightweight nature, high porosity, and specific surface area, which attribute to their outstanding thermal insulation properties. The inherent thermal stability of the PIR moieties, combined with great insulating performance, renders PIR aerogels highly suitable for building insulation applications. Nevertheless, materials containing isocyanurate obtained through direct trimerization of aromatic isocyanates exhibit brittleness, resulting in inferior mechanical performance. In order to enhance the processability of the PIR aerogels, we propose a cocyclotrimerization approach involving mixtures of mono- and difunctional aromatic isocyanates. This approach is designed to develop a PIR network with decreased cross-linking density and brittleness. Herein, we developed an array of PIR aerogels from different alkyl chain-modified isocyanate mixtures. The resulting PIR aerogels exhibited high porosity (>89%), a large surface area (∼300 m2/g), superinsulating performance with ultralow thermal conductivity (∼16.8 mW m-1 K-1), notable thermal stability (Td5% ∼ 250 °C), improved mechanical performance, and intrinsic hydrophobicity without the need for postmodification. These high-performance organic aerogels hold significant promise for applications requiring superinsulating materials.
摘要：
芳香族聚异氰脲酸酯（PIR）气凝胶被认为是先进的多孔材料，由于其轻质性质而被广泛研究。高孔隙率,和比表面积，这归因于其突出的隔热性能。PIR部分的固有热稳定性，结合良好的绝缘性能，使PIR气凝胶非常适合建筑绝缘应用。然而，通过芳族异氰酸酯的直接三聚获得的含有异氰脲酸酯的材料表现出脆性，导致机械性能较差。为了提高PIR气凝胶的加工性能，我们提出了一种涉及单官能和双官能芳族异氰酸酯混合物的共三聚方法。该方法旨在开发具有降低的交联密度和脆性的PIR网络。在这里，我们从不同的烷基链改性的异氰酸酯混合物中开发了一系列PIR气凝胶。所得PIR气凝胶表现出高孔隙率(>89%)，大表面积(~300m2/g)，具有超低导热系数的超绝缘性能（〜16.8mWm-1K-1），显著的热稳定性(Td5%~250°C)，改进的机械性能，和固有的疏水性，而不需要后修饰。这些高性能有机气凝胶对于需要超绝缘材料的应用具有重要的前景。
