The influence of classical and enzymatic treatment on the surface charge of cellulose fibres

Natural cellulose fibres comprise several non-cellulose compounds and cationic trash which cause problems during different adsorption processes such as dying, printing, final fiber finishing and coating. Therefore the pre-treatment (classical NaOH or environmental friendly enzymatic treatment, demineralisation) is the most important step in cellulose textile prefinishing - cleaning. An appropriate way to describe the success of different processes in fiber pretreatment which result in distinct surface charge is the determination of electrokinetic properties - zetapotential (ZP) 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. Cellulose fibers in an aqueous medium are negatively charged due to their characteristic carbonyl and hydroxyl groups. The degradation and removal of specific hydrophobic non-cellulose compounds which cover the primary wall of the cellulose polymer change the surface charge. The ZP is mainly influenced by waxes, their removal decreases the negative ZP. This result is obtained by the classical chemical process as well as by an environmentally friendly enzymatic treatment. Our results indicate that the progress of textile treatment and purification is reflected by the zetapotential of the fabrics. This method enables the estimation of the process'es progress and the interaction between components of the liquid phase and the fibre surface.