Submitted to: Proceedings Of The American Association Of Textile Chemists And Colorists
Publication Type: Proceedings
Publication Acceptance Date: 11/6/2012
Publication Date: N/A
Citation: Interpretive Summary: Previous research on the effect of cotton substrate characteristics on the adsorption of aqueous solutions of a cationic biocide has shown that greige cotton substrates adsorb significantly more cationic surfactant than do bleached cotton substrates. Subsequent research has shown that the presence of pectin and waxes in the outermost primary wall of greige fibers was responsible for the observed increase adsorption of cationic surfactant by the unscoured and/or unbleached samples. In general, industrial and consumer wipes are primarily comprised of exclusively synthetic fibers or a blend of synthetic fibers with a small amount of either cotton fibers or pulp. This work compares the adsorption of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) onto cotton, synthetic, and cotton-polyester blend nonwoven fabrics. The adsorption of ADBAC onto the various nonwoven fabrics was investigated at varying immersion times and surfactant concentrations using UV-Vis absorption spectroscopy. The adsorption of the cationic biocide was then controlled by coformulating the surfactant solution with electrolytes, nonionic surfactants, small quaternary ammonium molecules, and alcohol. Via coformulation of the surfactant solution, the adsorption of ADBAC was either greatly reduced or eliminated altogether. The data obtained from the depletion method was used to elucidate the adsorption kinetics and verify the general surface orientation of the surfactant molecules by graphing the adsorption isotherms for each nonwoven.
Technical Abstract: The adsorption of a cationic biocide on various cotton and synthetic nonwoven fabrics was investigated using UV-Vis absorption spectroscopy. The results reveal that rayon and greige cotton nonwovens adsorb nearly three times more cationic biocide than comparable bleached cotton substrates. Polyester nonwovens, which do not have a surface charge in aqueous solutions, adsorbed negligible amounts of the cationic biocide. The presence of pectin and natural waxes in greige fibers was found to play a significant role in the adsorption of cationic surfactant by greige cotton nonwovens. It was found that the adsorption of the cationic biocide can be controlled by varying the chemical and physical properties of the surfactant solutions. Co-formulating the biocide solution with electrolytes or nonionic surfactants greatly reduced and/or eliminated the adsorption of the cationic biocide on the cotton-based nonwoven substrates. The results of this research are expected to aid the development of environmentally friendly cotton-based antimicrobial wipes.