Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2014
Publication Date: 4/24/2015
Citation: Nam, S., Slopek, R.P., Condon, B.D., Sawhney, A.P. 2015. Effect of polyester blends in hydroentangled raw and bleached cotton nonwoven fabrics on the adsorption of alkyl-dimethyl-benzyl-ammonium chloride. Textile Research Journal. 85(12):1221-1233.
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 16. 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 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. A kinetic study of the adsorption of ADBAC, a cationic biocide, onto various cotton, cotton-blend, and synthetic nonwoven fabrics from aqueous solutions has revealed that the adsorption can be best described by a pseudo second-order kinetic model. The rayon nonwoven substrates exhibited the fastest rate of cationic surfactant adsorption and adsorbed the greatest total amount of ADBAC from solution. Greige cotton substrates adsorbed slightly less ADBAC than did the rayon substrates, but 2.8 times more than comparable bleached cotton nonwoven substrates. The uncharged polyester substrates were found to adsorb essentially no ADBAC, and when blended with greige and bleached cotton fibers, the polyester fibers reduced the rate and total amount of ADBAC adsorbed in blended nonwovens. The adsorption isotherm data were experimentally obtained by varying the concentration of ADBAC Results supported the trend observed in the kinetic data which showed that the rayon and greige cotton substrates adsorbed more ADBAC than did the bleached cotton substrates. When plotted, the adsorption isotherms of the bleached samples exhibited the standard S-shaped curve, while the greige cotton and rayon samples were more linear before reaching a plateau near the critical micelle concentration of the surfactant. As the amount of polyester in the bleached cotton blends was increased, the adsorption isotherms became increasingly similar to those of the greige cotton and rayon nonwoven samples. The information ascertained in this study is expected to aid in the development of an environmentally friendly cotton-based nonwoven antimicrobial wipe for the disinfection of hard surfaces.
Technical Abstract: The adsorption kinetics and isotherms of alkyl-dimethyl-benzyl-ammonium chloride (ADBAC), a cationic surfactant commonly employed as an antimicrobial agent, on hydroentangled nonwoven fabrics (applicable for wipes) including raw cotton, bleached cotton, and their blends with polyester (PES) were studied at room temperature. The adsorption kinetics of ADBAC on all nonwoven fabrics studied was best described by the pseudo first-order kinetic model. Unlike bleached cotton/PES blends, the equilibrium adsorption capacities of ADBAC on raw cotton/PES blends were enhanced in comparison with predictions based on the binary mixing rule. The adsorption rates for raw cotton, determined by the KASRA and Elovich models, were significantly greater than those for bleached cotton, resulting in a rapid decrease of adsorption rates when blending with PES, which has a negligible interaction with ADBAC. This distinctive adsorption property of raw cotton was attributed to its unique surface characteristics induced by the hydroentangling process: retained pectin, partial removal of waxes, and surface fibrillation, which enhance electrostatic interaction, hydrophobic interaction, and accessible surface area to ADBAC, respectively. In adsorption isotherms, the complex adsorption system of hydroentangled raw cotton resulted in lack of distinction between Regions I and II and a non-linear decrease in maximum adsorption capacity and monolayer adsorption capacity, calculated by the Langmuir and Langmuir-type equations, respectively, as a function of PES blend ratios.