Plasma-based regenerable antimicrobial finishing for cellulosic textile materials

Abstract

Owing to the advance in hygroscopicity and permeability, cotton fabrics are considered as paramount textiles. Just because of the good hygroscopicity, cotton fabrics are attacked easily by microorganism. This drawback can be made up by antimicrobial finishing of cotton fabrics. The ideal antimicrobial materials should be regenerable and safe for human and environment. This study investigates the application of nitrogen plasma treatment in antimicrobial finishing processes for cotton fabrics to impart cotton fabrics with regenerable antimicrobial property. In this research, nitrogen plasma treatment used independently to provide antimicrobial finishing for cotton fabrics was firstly studied. Then plasma treatment was combined with pad-dry-cure process of fabrics coated with chitosan and 5, 5 - dimethylhydantoin (DMH), separately. In all of these finishing processes, the fabric was chlorinated with sodium hypochlorite to impart antimicrobial properties and functions. The finishing processes were optimized by an orthogonal array testing strategy (OATS). The influences of parameters, e.g. discharge power of plasma, flow rate of nitrogen, moving speed of fabrics, concentration of finishing agent, curing temperature, concentration of sodium hypochlorite, and time of chlorination, in the antimicrobial finishing processes on the regenerable antimicrobial activity of cotton fabrics were studied. Ultraviolet-visible spectroscopy (UV-vis), Scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize the properties of cotton fabric, including concentration of chlorine, morphological properties and functional groups on the cotton fabrics. Tearing strength and weight loss of treated fabrics were also evaluated to study the interaction of plasma treatment with cotton fabrics. The antimicrobial results showed that cotton fabrics treated with plasma independently or finished with the combination processes of plasma and pad-dry-cure process had inhibition of bacteria, Staphylococcus (S. aureus), and the antimicrobial property was regenerable.