Mateja Kert

UV protective properties of cotton fabric treated with plasma, UV absorber, and reactive dye

The influence of water vapor plasma on the adsorption of UV absorber during the reactive dyeing of bleached and mercerized cotton fabric was examined. Exhaust dyeing of untreated and plasma-treated cotton was performed using a reactive dye Cibarcon Deep Red S-B and a commercial UV absorber Tinofast CEL. Blank dyeing was performed as a control experiment. Fourier transform infrared spectroscopy (FTIR) was used to identify the presence of the UV absorber on the cotton fabric, whereas scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze surface changes of untreated and plasma-treated dyed samples. The CIELAB color values and ultraviolet protection factor (UPF) of the samples were determined spectrophotometrically. Wash and light fastness of samples was performed also. The results reveal that the UPF of cotton increases after UV absorber treatment and that plasma treatment increases the adsorption of UV absorber during dyeing process, especially at higher dye concentrations. The enhanced adsorption of UV absorber onto plasma-treated cotton is the result of the increased concentration of oxygen containing functional groups on the cotton surface after plasma treatment, confirmed by XPS. The UPF of plasma-treated cotton samples is decreased after washing and increased after exposure to xenon light.

Preparation of Functional Stimuli-responsive Polyamide 6 Fabric with ZnO Incorporated Microgel

A new functional, stimuli-responsive microgel coating on polyamide 6 (PA6) fabric with simultaneous temperature (T)and pH-responsive moisture management, UV protection and photocatalytic self-cleaning properties was prepared by applying poly-(N-isopropylacrylamide)/chitosan (PNCS) microgel in combination with ZnO nanoparticles to PA6 fabric. Two diff erent application procedures were used: (i) the application of PNCS previously functionalized with a ZnO nanoparticles suspension and (ii) the application of PNCS with the subsequent application of a ZnO nanoparticles suspension. The coatings were fabricated on the untreated PA6 fabric as well as on fabric previously modifi ed by the silica matrix created by the sol-gel precursor iSys MTX in order to increase the adsorption ability and uniformity of the coating. The chemical and morphological properties of the coated PA6 samples were determined by SEM and FTIR analyses. Stimuli responsiveness and functional properties were assessed by the moisture content, water vapour transmission rate, water uptake, UV protection and photocatalytic self-cleaning measurements. The results show that the application procedure as well as the pretreatment of PA6 fabric greatly infl uenced the properties of the coating. Accordingly, the most appropriate procedure included the creation of a silica matrix on the PA6 fi bres followed by the application of PNCS and subsequent application of ZnO. In this case, the modifi ed PA6 fabric exhibited high T and pH responsiveness due to the swelling/de-swelling activity of the PNCS microgel, as well as good UV protection with UPF equal to 18.8 and photocatalytic self-cleaning properties that are even higher than those in the case of the one-component coating with ZnO.