Surface properties of textile cellulose as a function of processing steps

Natural cellulose fibers comprise several non-cellulose compounds and cationic trash which causes problems during different adsorption processes such as dyeing, printing, final fiber finishing and coating. Therefore the pretreatment (classical NaOH, demineralization, oxidative bleaching) is the most important step in cellulose textile finishing. Alternative ways to describe the success of different processes in fiber pretreatment which result in distinct surface charge and hydrophilicity are the determination of electrokinetic properties and the water uptake of fibers and textile materials. The zetapotential was determined by streaming potential measurements as a function of the pH and the surfactant concentration in the liquid phase. The water uptake was observed measuring the changes of the ultrasound intensity caused by the water penetration into dry cellulose fabric. The degradation and removal of hydrophobic non-cellulose compounds which cover the primary hydroxyl and carboxyl groups of the cellulose polymer is clearly shown by an increase of the negative ZP. This observation correlates well with the penetration measurements showing improved hydrophilicity for example after NaOH treatment or extraction. The progress of the fiber processing (cleaning, pretreatment) is reflected by the surface charge as well as the hydrophilicity of the fiber.