Influence of Porosity and Yarn Linear Density on the Thermal Behaviour of Polyester Warp Knitted Spacer Fabrics

Spacer fabrics are 3D fabrics comprising of two outer fabric layers that are joined together and kept apart by an insert of spacer yarns, mostly monofilaments. This creates a ventilated layer of air, allowing heat and moisture to escape. Material types and the surface characteristics of the layers influence the thermoregulation properties of the spacer fabrics. In this study, Warp Knitted Spacer Fabrics (WKSF) were designed with polyester multifilament in face and back surface layers and are linked by middle layer made of polyester monofilament. Three-factorial Box and Behnken experimental design was used and the effects of different polyester filament denier combinations of face, middle and bottom layers and the porosity of the fabric on the thermoregulation properties were analysed. The analysis of variance (ANOVA) and response surface design (RSM) were used for the optimization of porosity and thermal properties of the WKSF. The experimental result indicates that among the three layers of polyester WKSF, the face layer has exceptional influence on all the responses and the bottom layer has trivial or no impact.