Moisture management properties of plain knitted fabrics made of natural and regenerated cellulose fibres

Abstract

Moisture management is a complicated process which is known to be influenced by a variety of fabric characteristics such as fibre nature (hydrophilic or hydrophobic), porosity and thickness. There are different aspects of the moisture management properties of textile materials since water transport in textile materials can be in the form of liquid and vapour. The ability of textile materials to transfer water vapour allows the human body to keep thermal balance due to evaporation. With stronger physical activity of a person when the body produces a large amount of heat, the skin perspiration increases (in order to regulate the body temperature) and liquid sweat should be taken from the skin, otherwise it will worsen the sense of comfort. The aim of this research was to investigate the factors influencing moisture management properties of plain knitted fabrics at the three scale levels, i.e. microscopic (fibre type), mesoscopic (yarn geometry) and macroscopic (fabric porosity) levels. Plain knitted fabrics were produced from the two-assembled hemp, cotton and viscose yarns under controlled conditions so as to be comparable in basic construction characteristics, but varying in yarns geometry. Evaporative resistance test reflecting vapour transport and water distribution test reflecting liquid transport in the knitted fabrics were conducted. To determine the statistical importance of the results, analysis of variance (ANOVA) was applied. As a consequence of the geometry and deformation behaviour of the fibres used and spinning techniques applied, the yarns differed in both packing density and surface geometry, thus determining the pore distribution. Due to loose structure of the cotton yarn, the cotton knitted fabric was characterised by the lowest free open surface (macroporosity) exhibiting the lowest both water vapour and liquid permeability. Although having the highest macroporosity, the water vapour and liquid transport capability of the hemp knitted fabric was lower than that of the viscose knit. The best moisture management properties of the viscose knitted fabric were resulted from viscose affinity for water absorption and increased surface area of the viscose yarn. The results obtained proved that variations in any of the hierarchical structure levels can modify moisture transport ability of textile fabrics. Therefore, the moisture management properties of textile materials can be guided in a desired direction by the appropriate selection of fibres and careful design of yarn structure.