HNTs/SiO2 dual-network aerogels with improved strength and thermal insulation

• Published in: Journal of sol-gel science and technology 2018-12, Vol.88 (3), p.519-527
• Main Authors: Liu, Hongli, Li, Shixiong, Li, Hongyan, Chen, Zhong, Li, Jing, Li, Yajing
• Format: Article
• Language: English
• Subjects: Aerogels; Ceramics; Chemistry and Materials Science; Composites; Compression tests; Compressive properties; Compressive strength; Conductivity; cryogels; Energy transmission; etc.; Glass; Heat conductivity; Heat transfer; Inorganic Chemistry; Insulation; Materials Science; Microscopy; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Nano- and macroporous materials (aerogels; Raw materials; Scanning electron microscopy; Silicon dioxide; Tetraethyl orthosilicate; Thermal conductivity; Thermal insulation; Transmission electron microscopy; xerogels
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-018-4851-3

Dual-network aerogels (HPSA) with improved mechanical property and thermal insulation were prepared by vacuum impregnation of HNTs/PVA aerogels (the first network aerogel, HPA) in tetraethoxysilane (TEOS). Scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and N 2 adsorption–desorption analysis were used to study micromorphology and microstructure of HPSA, while compression tests and thermal conductivity tests were used to investigate related properties. The results showed that the dual-network frame was successfully constructed, this enabled HPSA to display enhanced compressive properties with increased HNTs content. The addition of silica sol improved the mesoporous characteristics including specific surface area and pore volume and also reduced the thermal conductivities. The first network made it possible for HPSA to possess good mechanical property, while SiO 2 aerogel allowed HPSA greater thermal insulation. The obtained aerogel samples exhibited a high compressive strength (i.e., 1.36 MPa) and a low thermal conductivity (i.e., 0.022 W/(m K)). HNTs/SiO 2 dual-network aerogels with improved strength and thermal insulation could show great potential in a wide variety of applications. Highlights Novel HNTs/SiO 2 dual-network aerogels were successfully prepared through cheap raw materials. The effects of HNTs content on the compressive strength and SiO 2 content on the thermal conductivity of aerogels were studied. The effects of dual-network frame on compressive strength and thermal conduction of aerogels were analyzed in detail by models.