The contribution deals with the influence of selected knitting parameters and the relaxation period on the structure and mechanical properties of plain jersey weft knitted fabrics made of cotton and elastane yarns. There are considerable differences in the behaviour of conventional knitted fabrics and fabrics with elastane yarns incorporated in the structure. Since one of the key factors in knitting is certainly the knitting yarn feeding load - it impacts the structure and properties of such knitted fabrics, the contribution presents the influence of the knitting yarn feeding load on the alteration in the mechanical properties of plain jersey wefl knitted fabrics. The results of the investigation indicate that the horizontal and vertical density and the fabric weight grow with a prolonged relaxation period and increase in the knitting yarn feeding load. Increasing the knitting yarn feeding load reduces the length of yarn in the loop. If cotton yarn is platted with elastane yarn, the length of the yarn in the loop is reduced by about 2 to 5%, as compared with yarn in a course without elastane yarn. The most prominent dimensional changes in the course and wales direction occurred for samples knitted with the highest feeding load of yarns. The best results of measuring structural parameters and dimensional changes in knitted fabrics during relaxation were exhibited by knitted samples with the lowest feeding load. Therefore, the feeding load of yarns should be taken into account when constructing knitted fabrics as it considerably affects fabric properties.

The impact of input tension of elastane and cotton yarns upon the structure and relaxation of plain jersey knitted fabrics is investigated. There are considerable differences in the behaviour of conventional knitted fabrics and the fabrics with elastane yarns incorporated in the structure. One of the key factors in knitting is certainly the input tension of the yarn, as it impacts the structure and properties of such knitted fabrics. Horizontal and vertical density, as well as surface mass grows with the prolonged relaxation period as they grow with the increase of knitting yarn input tension. Increase in knitting yarn input tension reduces the length of the yarn in the loop. If cotton yarn is platted with elastane one, the length of the yarn in the loop is reduced for about 2 to 5%, as compared with the yarn in a course without the elastane yarn. This can result in horizontal streaks in the knitted fabric. The most prominent dimensional changes in the direction of the courses and wales occur with the samples knitted with the highest input tension on knitting yarns. The best results of measuring structural parameters and dimensional changes in knitted fabrics in relaxation have been exhibited by knitted samples with the lowest input tension. In constructing knitted fabrics input tension of the yarns should be taken into account, as it considerably affects fabric properties.

Postoje znacajne razlike u ponasanju klasicnih pletiva i pletiva sa ugrađenom elastanskom pređom. Elastanske pređe imaju veliku rastezljivost i elasticnost pa stoga znacajno utjecu na strukturu i svojstva pletiva. U radu je ispitivan utjecaj monofilamentne elastanske pređe na duljinu niti u ocici. Uocena je pojava da u redu gdje se platira pamucna pređa sa monofilamentnom elastanskom pređom duljina niti u ocici je manja za 2 do 5 % od duljine niti o ocici u redu gdje se plete samo s pamucnom pređom. Neujednacena duljina niti u ocici pojedinih redova negativno utjece na strukturu pa tako i na kvalitetu pletiva.