Changes in the Specific Charge Amount?on the Surface of Cotton Fibres during the?Alkali Pre-treatment Process

摘要

The aim of the pre-treatment process is to prepare cotton fabrics for subsequent technological?operations, which are, in the majority, carried out in aqueous solutions. The pre-treatment?processes modify, to some extent, the properties of cotton, resulting in a significant change?in their zeta potential, the amount of specific surface charge or free energy surface. This study?makes an assessment of the effect of the alkali pre-treatment process on changes in the?amount of negative specific charges on cotton knitted surfaces, known as cationic demand.?A “back-titration” method with the use of a Muetek PCD device was adopted for these?experiments. It was found that the conventional process of alkali treatment of raw cotton?knitted fabrics using sodium hydroxide in the presence of non-ionic surfactant reduced by?nearly 50% the amount of negative specific surface charge. Also, changes in weight loss and?improvements in the whiteness index, as well as the wettability of alkali pre-treated cotton?knitwear, were observed.