Effect of Knitting Structure and Polyethylene Content on Thermal-wet Comfort and Cooling Properties of Polyethylene/polyester Fabrics

Polyethylene is getting tremendous attention in personal thermal management textiles for summer, but there is lack of systematical coolness and thermal-wet comfort research in wearing knitting fabrics. In this work, two group of knitting structure were designed following a sandwich structure model that consisted of a middle layer of multifilament and two asymmetric outer layers. Nine bi-layer samples interknitted with polyester were fabricated with one face composed of polyester filaments and the other face built of polyethylene and polyester filaments. Textile parameters, such as knitting structure, polyethylene fractions and distribution in the inner layer, yarn composition and relative porosity, were considered. Breathability, thermal transfer properties, moisture management performance and dynamic cooling performance was measured and evaluated to investigate the thermal-wet and coolness relevant comfort properties of these fabrics. It was found that the fabrics knitted with tuck stitches have better air permeability, contact coolness, overall moisture management and dynamic cooling performance in comparison to the fabrics knitted with float stitches. The air permeability became better with the increasing proportion of polyethylene and the decreasing ratio of tuck stitch. The effective contact area of polyethylene with skin was beneficial to promote the transient thermal conductivity and dynamic cooling performance of fabric. The result also suggested that an asymmetric structure with meshes in the inner layer were beneficial to promote moisture management. Meanwhile, when the proportion of tuck stitch in inner layer was 6.25 %, the air permeability and heat transfer properties of fabric were the best. Moreover, independent tests had proved that the performance of transient and steady thermal conductivity of polyethylene/polyester fabric was the best when the mass ratio of polyethylene was 49.3 % in this study.