Thesis Details

Thesis Title: Durable Ionic-Modified Antistatic Fibers: A Combination of Nanotechnology and Atmospheric Plasma Treatment
Thesis Author: Sudhir Sarma
Abstract: The accumulation of static charge on textile material, and its subsequent discharge, presents major problems in the processing of textiles. It also becomes a marketing problem because consumers have to endure the unpleasant effects of static discharge like mild shocks, as well as the clinging and unwanted crumpling of fabrics. To combat the problem of static accumulation, antistatic finishes are added to the substrate. These finishes generally act by adding polar groups to the substrate, increasing the hydrophilicity and making it more amenable to dissipating away the excess charge. This research investigated the effect of silica nanoparticles and ionic monomers on improving the antistatic properties of commercial grade polyester/cotton fabrics. 65%- 35% polyester/cotton blended fabrics were treated with combinations of modified silica nanoparticles and ionic monomers like sodium vinylsulfonate and 2-acrylamido-2- methyl-1-propanesulfonic acid. The fabrics were exposed to atmospheric plasma to initiate the polymerization reaction on the fabric surface. The fabrics were then coated using a laboratory scale dip-pad process and were either air dried or oven dried depending on whether it was followed up by additional plasma treatment. The finished fabrics were evaluated using a surface resistance meter. The finished fabrics were also tested for durability to laundering. The types of experiments that were carried out ascertained the effect of different processing parameters on the performance of the antistatic finish. The experiments included: (1) application of different concentrations of silica nanoparticles to ascertain the effect of silica concentration on the finish properties; (2) the effect of plasma treatment time on the resulting finish; (3) the effect of plasma types, namely helium and helium-oxygen plasmas, on the resulting antistatic properties; and (4) the effect of plasma treatment procedure on the finish properties. Results of the conducted experiments showed that the modification of the fabric surface using silica particles and ionic monomers yielded the desired results. The antistatic properties of the finished fabrics did show a significant increase after the application of the chemicals, indicated by lowered resistivity values. In addition, the antistatic properties of the finished fabrics improved when they were exposed to atmospheric plasma as part of the treatment process, as opposed to just treating the fabric with a combination of polymerization initiators and monomers in the presence of thermal energy. Although the presence of silica particles did have an ameliorating effect on the static dissipating properties, with the best results being noticed at a silica concentration of 0.5 grams per liter (gpl) in the dispersion, the antistatic properties decreased first, and then increased sharply as the concentration of silica particles increased in the dispersion. The usage of different gases for plasma also played a role in determining the properties of the finish. Of the two plasma types used: helium and helium-oxygen, helium-oxygen plasma yielded better properties when used in conjunction with silica particles and the ionic monomers, as the resistivity values of the helium-oxygen treated polyester-cotton samples were up to ten times lesser than the values obtained by helium plasma treatment alone. The rinsed samples showed a significant loss in antistatic properties, with the rinsed samples showing resistivity values that were higher by two orders of magnitude than the treated samples, indicating that the durability of the applied finish needs to be improved. The results obtained would fuel further interest in both the usage of nanosilica and the plasma treatment process to provide inexpensive and environmentally sustainable treatment.