The influence of structural variations on wool fabrics air permeability

Abstract

Woven fabrics are materials of a sophisticated structure. Basic structural parameters, the raw material, linear density of warp and weft yarn, number of yarn twist, warp and weft density, warp and weft crimp, as well as weave contribute to the obtained properties of the fabric. Certain basic parameters of the fabric can be controlled directly either during the preparatory processes or during the weaving process itself. There are some important structural parameters, however, for which no direct quantitative controls exist. Since all structural parameters are closely interdependent, the lack of direct control results in an imperfect control of the fabric structure. The subject of the investigation was how small variations in semi-worsted wool fabric constructional parameters influence the air permeability, and to which extent they can be controlled in the design process and weaving of fabrics. The experiment showed that yarn count, warp and weft density and warp and weft crimp are highly interrelated, leading to small variations in the fixed sett. The statistical significance of small variations in the groups of fabrics was confirmed by the analysis of variance. The analysis confirmed that there were no differences in mass, although all other structural parameters differed. Additionally, a post-hoc Bonferroni test showed that the structural parameters of the group of fabrics, which has a practically balanced structure, are always different to those of groups g2 and g3. Fabric alternations done on the same warp, in such a manner to achieve the same mass per square meter, showed that the change in weft yarn count and weft density influenced the fabric structure as a result of the crimp interchange. However, there was not a statistically significant difference among the three groups of fabrics when tested for air permeability.

Investigation of the Shrinkage and Air Permeability of Woolen Blankets and Blankets Made with Regenerated Wool

“…Low air permeability (1920.50 dm 3 /(m 2 s)) was also obtained for sample 3 woven with diamond twill. The given results of air permeability correspond to the studies published in references [ 23 , 24 , 25 ], where it was established that the value of air permeability changes depending on the increase in interlacing and the length of the floats. This was the reason for longer floats creating larger pores (spaces) in the weave and higher air permeability.…”

“…Sample 4, similar to Series 1, had low air permeability (1983.96 dm 3 /(m 2 s)), while an air permeability of 2127.58 dm 3 /(m 2 s)) for sample 5 with a derived basket weave was obtained. The air permeability of woolen woven fabrics depends on their structure parameters, including the weave [ 24 , 25 ]. The given results correspond to previously described results, which state that weaves with longer floats have higher air permeability.…”

“…This property is highly related to the porosity of the fabric, of which the methods of establishment are described in reference [ 23 ]. The structural parameters, such as the raw material, linear density of the warp and weft yarns, number of yarn twists, warp and weft density, warp and weft crimp, and weave, influence the porosity and air permeability of fabrics [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The influence of the structure of woolen fabric on its comfort properties and shrinkage has been described in only a few works [ 25 , 26 ]; thus, such investigations are very important.…”