Characterization and Role of Porosity in Knitted Fabrics

Abstract

Knitted fabrics are the preferred structures in athletic wear in which demand for comfort is a key requirement. Heat and liquid sweat generation during athletic activities must be transported out and dissipated to the atmosphere. A key property influencing such behaviors is porosity. Two parameters that characterize it are pore size and pore volume. One of the objectives in this research was to come up with models that can predict interyarn pore size and pore volume for simple weft knitted structures, from fabric particulars, such as courses and wales count, yarn size, stitch density, thickness and other geometrical details of the fabric, which characterize the structure. Such a model was developed that was based on the geometry of the unit cell of a single loop.

The experimental work in this thesis involved using a set of 8 knitted fabrics that differed in course count and examining their pore structure and porosity related characteristics. The values of pore size and pore volume were calculated, those of pore size were measured with image analysis and fluid extrusion procedures, and the role of these in determining fluid holding and air and fluid transport properties were determined. The effects of course count and washing on stitch density, stitch length, fabric thickness and pore size are examined in detail.