Electrokinetic properties of surface modified PETP fibres

The microporous structure of unmodified poly (ethylene terephthalate) PETP fibres was investigated by small-angle X-ray measurements in order to determine the content, size and shape of micro-voids in the fibres. Because of the compact and highly crystalline morphology of the chemically weakly reactive PETP fibres, the rate of diffusion within the fibres or adsorption on the surface is very low. Therefore a technique for modifying polyester fibre surface to change the dyeability, water sorption properties and electrokinetic characteristics have been suggested and used. It includes the adsorption of some electrolytes on the fibre surface. In order to study the obtained fibre surface changes the zeta-potential ζ was determined by streaming potential measurements as a function of pH. PETP fibres exhibit high negative ζ plateau value, due to their strong hydrophobicity and non-ionic character. The application of the surfactant changes the electrokinetic properties with respect to the adsorption process conditions.