Lledó Jaime, Martín-de León Judith, Gómez Álvarez-Arenas Tomás E, Rodríguez-Pérez Miguel Ángel, Merillas Beatriz
Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, Faculty of Science, Campus Miguel Delibes, University of Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain.
BioEcoUVA Research Institute on Bioeconomy, University of Valladolid, 47011 Valladolid, Spain.
Gels. 2025 Jan 7;11(1):44. doi: 10.3390/gels11010044.
In the present work, the influence of the addition of graphene nanoplatelets presenting different dimensions on polyurethane-polyisocyanurate aerogel structure and properties has been studied. The obtained aerogels synthesized through a sol-gel method have been fully characterized in terms of density, porosity, specific surface area, mechanical stiffness, thermal conductivity, and speed of sound. Opacified aerogels showing high porosity (>92%) and low densities (78-98 kg/m) have been produced, and the effect of the size and content of graphene nanoplatelets has been studied. It has been observed that formulations with less than 5 wt.% of graphene nanoplatelets larger than 2 microns can effectively reduce the total thermal conductivity by absorption and scattering of the infrared radiation, reducing the heat transfer by this mechanism. The resulting opacified samples are highly insulating materials, with thermal conductivities less than 18 mW/m·K. Moreover, it has been observed that smaller particles with ca. 200 nm of average length can promote an increase in the elastic modulus, therefore obtaining stiffer aerogels, combined with thermal conductivities lower than 20 mW/m·K. Results have been studied in detail, providing a further understanding of the mechanisms for improving the final properties of these materials, making them more suitable for industrial applications.
在本研究中，已对添加具有不同尺寸的石墨烯纳米片对聚氨酯 - 聚异氰脲酸酯气凝胶结构和性能的影响进行了研究。通过溶胶 - 凝胶法合成的所得气凝胶已在密度、孔隙率、比表面积、机械刚度、热导率和声速方面进行了全面表征。已制备出具有高孔隙率（>92%）和低密度（78 - 98 kg/m³）的不透明气凝胶，并研究了石墨烯纳米片的尺寸和含量的影响。已观察到，石墨烯纳米片含量低于5 wt.%且尺寸大于2微米的配方可通过红外辐射的吸收和散射有效降低总热导率，从而通过该机制减少热传递。所得的不透明样品是高度绝缘的材料，热导率低于18 mW/m·K。此外，已观察到平均长度约为200 nm的较小颗粒可促进弹性模量的增加，从而获得更硬的气凝胶，同时热导率低于20 mW/m·K。已对结果进行了详细研究，进一步了解了改善这些材料最终性能的机制，使其更适合工业应用。
