Linhares Teresa, Carneiro Vitor H, Pessoa de Amorim Maria T, Durães Luisa
University of Coimbra, CIEPQPF, Department of Chemical Engineering, 3030-790 Coimbra, Portugal.
2C2T-Centre for Textile Science and Technology, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal.
Gels. 2023 Jul 5;9(7):548. doi: 10.3390/gels9070548.
Silica aerogels are highly porous materials with exceptional thermal insulation performance. They become even more attractive if combined thermal and acoustic insulation is achieved. Silica aerogel composites reinforced with fibres are an ingenious way to surpass the fragility stemmed from the aerogel's intrinsic porosity, and textile fibres are good sound absorption materials. Reclaimed fibres are a relatively low-cost feedstock and were obtained in this work exclusively through mechanical processes from textile wastes, thus promoting the concept of circular economy, namely for cotton, polyester and wool fibres. These reclaimed fibres were used as reinforcement matrices for silica aerogel composites obtained from sol-gel transformation of tetraethyl orthosilicate and isobutyltriethoxysilane/or vinyltrimethoxysilane precursors and dried at ambient pressure after silylation. Silica aerogel composites reinforced with reclaimed cotton fibres had the best sound absorption coefficient (a peak value of 0.89), while the polyester-reinforced composite exhibited the lowest thermal conductivity ( ~24 mW m K, ). The better combined results on thermal and acoustic insulation were achieved by the wool-reinforced composites. The thermal conductivity values were less than 27 mW m K, and the sound absorption coefficient achieved a peak value of 0.85. Therefore, the aerogel composites developed here can be selected for thermal or/and acoustic barriers by choosing a suitable type of fibre. Their design and preparation protocol followed environmental-friendly and cost-effective approaches.
二氧化硅气凝胶是具有卓越隔热性能的高度多孔材料。如果能实现热绝缘和声绝缘相结合，它们会更具吸引力。用纤维增强的二氧化硅气凝胶复合材料是一种巧妙的方法，可以克服气凝胶固有孔隙率带来的脆性，而纺织纤维是良好的吸声材料。回收纤维是一种成本相对较低的原料，在这项工作中，它们完全通过机械工艺从纺织废料中获得，从而推广了循环经济的概念，即针对棉、聚酯和羊毛纤维而言。这些回收纤维被用作二氧化硅气凝胶复合材料的增强基体，该复合材料由原硅酸四乙酯和异丁基三乙氧基硅烷/乙烯基三甲氧基硅烷前驱体通过溶胶 - 凝胶转变制得，并在硅烷化后于常压下干燥。用回收棉纤维增强的二氧化硅气凝胶复合材料具有最佳的吸声系数（峰值为0.89），而聚酯增强复合材料的热导率最低（约24 mW m⁻¹ K⁻¹）。羊毛增强复合材料在热绝缘和声绝缘方面取得了更好的综合效果。其热导率值小于27 mW m⁻¹ K⁻¹，吸声系数峰值达到0.85。因此，通过选择合适的纤维类型，这里开发的气凝胶复合材料可被选作热障或/和声障。它们的设计和制备方案遵循了环保且经济高效的方法。
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