Sustainable antimicrobial finishing of cotton fabrics by chitosan UV-grafting: from laboratory experiments to semi industrial scale-up

The topic of the present study was the antibacterial finishing of cotton fabrics by ultraviolet grafting of chitosan biopolymer on fiber surface. A first part, carried out at laboratory level, deals with the optimization of process parameters, followed by a deep characterization of treated samples, revealing the effectiveness of the treatment. Therefore, the applied method was carefully monitored, laboratory apparatus were used and just samples of small surface were prepared by UV-grafting of pure chitosan in inert atmosphere, on dried samples, as recommended for radical curing. To test the feasibility of the proposed treatment even at semi-industrial level, in the second step of the study larger fabric samples were impregnated by foulard with a commercial chitosan solution and then were irradiated, both dried and wet, with an high power UV lamp, in air. Moreover, samples add-on was significantly reduced in order to hold down the finishing cost. White and dyed samples were treated and evaluated in terms of conferred antibacterial activity, yellowing or color changes and final hand. Eventually, treatment fastness to domestic laundering was tested. Obtained results confirmed the previous laboratory results: a strong antibacterial activity with good washing fastness was achieved by irradiation of the samples even wet and in air. It was obtained with a chitosan add-on percentage lowered till 0.3 wt% with a negligible affection of color or hand properties of the fabric.