Adsorption capacity, kinetics, and thermodynamics of chitosan nanoparticles onto cotton fabrics without any chemical binders

Abstract

The stable adsorption of chitosan nanoparticles (CNs) onto cotton fabrics was successfully developed without any chemical binders. The adsorption kinetics, thermodynamics, and capacities under different experimental conditions were investigated. The structure and laundering durability of CNs-adsorbed cotton fabrics (CNs-cotton) were also characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and Thermo Gravimetric Analysis (TGA). The adsorption capacities of cotton for CNs declined with the increasing CNs particle size and temperature. By contrast, adsorption capacities increased with the increasing adsorption pH and CNs mass concentration. The kinetic adsorption of CNs onto cotton fabrics was found to follow the pseudo-second-order kinetic model. The adsorption mechanism reflected a complex process, and the intra-particle diffusion was not the only rate-limiting step. The transfer and diffusion rates progressively increased with the decrease of adsorption temperature and CNs particle size. The negative values of the standard Gibbs free energy changes (ΔG°) and the standard enthalpy (ΔH°) indicated that the adsorption was exothermic and spontaneous at 5–75°C. The superior laundering resistance of CNs-cotton was demonstrated after 30 consecutive washes, thereby proving the stable adsorption of CNs onto cotton fabrics without chemical binders. POLYM. COMPOS., 36:2093–2102, 2015. © 2014 Society of Plastics Engineer