In-Plane and Through-Plane Porosity in Coated Textile Materials

Many industrially important textile materials are in the form of sheets. Their porosity is generally determined by measuring their flow characteristics parallel to the thickness. However, their properties parallel to the thickness direction (through-plane porosity) and parallel to the plane of the sheet (in-plane porosity) are not the same. For many applications, such porosity data are essential for designing more efficient materials. Equipment has been designed to measure pore characteristics in such materials in both in-plane and through-plane directions. The equipment yields reproducible data. The bubble points in the two directions are considerably different from each other. The results are consistent with the fibrous nature of the textile.