Relationships between permeability properties and structural-geometrical properties of fabrics

The permeability properties of fabric are an expected performance property of textile structures used in different areas. The permeability properties of fabric occurs as a function of environmental properties, primarily pore properties formed by the structural properties of the fabric, and the properties of fluid. Therefore, the structural factors that determine the pore structure of the fabric should be chosen in the most suitable way while designing a product for a specific usage area. In this study, the relations between the permeability and structural properties of woven fabrics, which have a wide usage area such as clothing and technical textiles, are examined by the help of the data obtained from a group of test fabrics which is produced by warp and weft threads of the same count and which has different weave types and settings.In the study, permeability properties of the fabric are examined primarily by dividing into two regions, namely the inter-yarn pore regions and the inter-fiber pore regions. In order to define the inter-yarn pore properties, two-dimensional (2-D) and three-dimensional (3-D) unit pore cell models and 3-D weave unit models are defined theoretically by using structural properties such as setting, yarn count, fabric thickness. In addition, the pore properties are determined from the obtained surface and cross-sectional fabric images by image analysis method. The approach, which best defines the relation in-between for different fabric structures, is analyzed by examining the relation between the inter-yarn pore properties and the structural and permeability properties of the fabric. The intra-yarn pore properties are defined theoretically both by being measured from the cross-sectional images and by using fiber and yarn properties, and are determined by image analysis method, which is both fast and objective. After the pore properties determined by the structural and geometrical properties of the fabric are defined for both pore regions by different approaches, permeability results occurring as both through and in-plane directions are theoretically estimated by using the obtained pore properties in the flow equations. Consequently, it was found that the results of 2-D approaches were insufficient to exhibit the differences of fabrics having different weave types and the 3-D structure of the fabric should always be taken into consideration during predicting the permeability by using pore parameters. Keywords: permeability, porosity, pore size, image analysis method