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To study the adsorption to pure oil and oil-water mixture, cattail fiber waddings with different fibers, wadding structures, blending ratios were prepared. Oil absorbencies in the pure oils and oil-water mixtures were tested and evaluated. The analysis showed that cattail fiber waddings have better adsorption performance to pure oil and oil-water mixture, which is higher than 20 g/g. The retention rate of pure oil is higher than 90%, while retention rate of oil-water mixture decreases to 68%. With the increase of wadding thickness and cattail ratio, the oil adsorption and retention of composite waddings are heightened. The oil-retention declines with the blending of polypropylene (PP) fiber. The oil adsorption of kapok fiber is better than that of cattail fiber and PP fiber. Therefore, oil adsorption performance is improved through adjusting the fiber ratio and porous structure.

To study the frequency response characteristics of knitted fabric-based frequency selective surface (FSS), high-pass knitted fabric-based FSS were designed and prepared. The electromagnetic transmission characteristics were tested in a microwave anechoic chamber. The results show that weft-knitted fabric based FSS has high-pass and low-resistance electromagnetic properties. When the placement direction of the knitted fabrics and the polarization mode of electromagnetic wave are different, the frequency response characteristics are distinct. When the ratio of conductive yarns increases, the electromagnetic wave shield ability and breathability of knitted fabric based FSS are enhanced. The shielding ability of the fabric increases with the density, but the permeability of the fabric decreases. As the incident angle of electromagnetic wave increases, the electromagnetic wave component entering the fabric decreases, and the electromagnetic wave passing through the fabric decreases. Therefore, under the premise of wear comfort, the frequency response characteristics of knitted fabrics can be controlled and selective transmission of electromagnetic wave can be achieved by designing the structure and weaving parameters of knitted fabrics and adjusting the polarization mode and incidence angle of electromagnetic wave.