Study on thermal, mechanical, and wettability properties of three-dimensional weft-knitted spacer fabrics with various silica aerogels coating

Abstract

This study investigated the thermal, mechanical, and oil absorption-retention properties at various temperatures (20°C, 30°C, 40°C, 50°C, and 60°C) of three-dimensional (3D) weft-knitted spacer fabrics with optimal performance of silica aerogel coating that demands exceptional attention. Silica aerogels and (silica aerogels + poly(vinyl-alcohol)) sols were prepared and coated on 3D weft-knitted spacer fabrics to study and compare the basic properties, i.e. thermal resistance, thermal conductivity, tensile strength, initial modulus, compression, bending rigidity, wettability, oil absorption, and retention capacity. The scanning electron microscopy and Fourier transform infrared spectroscopy studies were completed to understand the influence of both coatings on 3D weft-knitted spacer fabrics such as surface morphology and molecular interaction. The tensile, bending, and compression tests of 3D weft-knitted spacer fabrics were accomplished to check their durability, bendability, and compressibility. All the coated samples (both silica aerogels and (silica aerogels + poly(vinyl-alcohol))) showed greater thermal resistance (0.0971 ± 0.0003 m2 KW−1 and 0.0912 ± 0.0005 m2 KW−1) and lower thermal conductivity (0.0309 ± 0.0001 Wm−1 K−1 and 0.0329 ± 0.0002 Wm−1 K−1) with better thermal stability than the uncoated samples, most specifically coated sample 5. Besides, coated sample 5 exposed higher oil absorption ((7.91 ± 0.06 g/g and 7.88 ± 0.06 g/g) and (7.56 ± 0.04 g/g and 7.53 ± 0.04 g/g)) and retention ((90.10 ± 0.53% and 89.07 ± 0.55%) and (92.47 ± 0.49% and 91.43 ± 0.47%)) capacity for vegetable and engine oil in all conditions, especially at 40°C. The outcomes demonstrated that both coatings played a vital role in the thermal, mechanical, and wettability properties of 3D weft-knitted spacer fabrics with statistically significant performance ( p < 0.05). Moreover, these new types of sorbents (3D weft-knitted spacer fabrics) have better consequences in most cases than conventional knitted, woven, and nonwoven sorbents. Hence, these 3D weft-knitted spacer fabrics could be used for industrial applications as eco-friendly and multifunctional oil sorbent materials.