Study on heat and moisture vapour transmission characteristics through multilayered fabric ensembles

The present paper reports a detailed study on heat and moisture vapour transmission characteristics of different types of multilayered fabric ensembles. Two sets of multilayered fabrics have been prepared. In first set, two types of carded web produced from acrylic and polyester fibres with five different areal densities in each fibre type have been used as middle layer. In second set, different types of fabrics, namely woven, knitted, felt, single-sided fleeced and double-sided fleeced fabrics made from wool fibre, have been used as middle layer. In both the sets, two types of inner and outer layer fabrics have been used. Silk and polyester woven fabrics have been used as inner layer and plain woven nylon coated and polytetrafluoroethylene (PTFE) coated fabrics have been used as outer layer. In both the sets, silk inner layer fabric ensembles show higher thermal resistance and lesser water vapour permeability than polyester fabric ensembles. Among the first set of multilayered fabrics, the fabric ensembles with acrylic fibre web show slightly higher thermal resistance and lesser moisture vapour permeability than fabric ensembles with polyester fibre web. Of all the fabrics, the type of outer layer used has no significant effect on the thermal transmission properties of multilayered fabrics. In the first set of multilayered fabrics, irrespective of the type of fibres, the increase in areal density of the fabric increases the thermal resistance and reduces moisture vapour transmission of the fabrics. In the second set of multilayered fabrics, woven, felt and knitted fabric ensembles show lesser thermal resistance and moisture vapour transmission than the fleeced fabric ensembles.