Comparison of Surface Area Covered by Adsorbed Dye Molecules in Acid Dye Solution C Potential Method with BET Specific Surface Area of Nylon 6 Fiber

Abstract

The surface area covered by adsorbed dye molecules on the fiber, which is determined from the slope of the surface day adsorption vs. total dye adsorption curves C potential method-, was investigated for nylon 6 fiber treated under different conditions of spinning, drawing and heat-setting, in acid dye solution. The surface area was compared with the BET specific surface area of the fiber determined by the adsorption of nitregen and water vapor. It was suggested that both surface areas are independet of spinning temperature and dependent on draw ratio and heat-setting condition, and that they are governed by the change in the crystallinity and the birefringence. The surface area covered by adsorbed dye molecules was always larger than that determined by the adsorption of nitrogen (about 10³ cm²/g-fiber). Moreover, the former was of the same order as that determined by the adsorption of water vapor (about 10⁶ cm²/g-fiber), but it had slightly larger value than the above. The surface area of wet-heat-set fiber covered by adsorbed dye molecule and determined by the adsorption of water vapor gave abnormally high values.