Assessment of the Comfort Properties of Rib Weft Knitted Fabrics with Different Elastic Yarn Feeding Rates

Weft knitted fabrics are a group of textiles that are used in the production of clothing, especially sportswear, due to the specific configuration of the thread in the form of a loop in the fabric and having elastic properties; Therefore, the examination of comfort characteristics of this category of textiles is of particular importance. In this regards,, in this study, four groups of rib weft knitted fabrics made of polyester/lycra was used, while the feeding amount of elastic yarns in these fabrics was different. In order to evaluate their comfort properties, features such as air permeability, water vapour permeability, thermal insulation properties, tensile and compressibility behaviour of these fabrics were measured and the effect of presence ratio of elastic thread in fabric on their comfort properties, was investigated. According to the results, due to the 50% rise of elasticity of the knitted fabric, the structure of the fabric becomes denser and the empty spaces in its structure decrease; therefore, properties such as water vapour permeability, air permeability, and heat resistance diminish about 40, 80 and 30%, respectively. On the other hand, as a result of increasing the proportion of elastic yarn in the fabric, the breaking force and elongation increase, while the initial modulus decreases. Moreover, by growing the feed amount of elastic thread in the fabric, the thickness of the fabric and the thickness recovery rise, however, its relative compressibility declines.