Effect of silver on cellulose fibre colour

Silver nanoparticles were embedded into cellulose fibres using N‐methylmorpholine N‐oxide as a direct cellulose solvent that was also the system from which silver nanoparticles were generated. The process of generation of silver nanoparticles in the N‐methylmorpholine N‐oxide enables the properties of cellulose fibres to be modified without any additional reducing agent, which makes this process more environmentally friendly. By varying the reaction time of the precursor with the N‐methylmorpholine N‐oxide, a range of nanoparticle sizes was obtained. The fibres contain the same concentration of silver, but, on account of the varying morphology of the nanoparticles, they show a range of colour shades. The primary aim of this study was to show how temperature and reaction time affect the basic parameters of the obtained nanoparticles (shape, size, and distribution in the polymer matrix of fibres), which consequently influences the colour of the modified cellulose fibres. Nanoparticles were characterised by dynamic light scattering and transmission electron microscopy methods, while the fibre hues were estimated by colorimetric analysis. Trichromatic coordinates of colour x, y were delineated, and the colour was identified by positioning the x and y values in the CIE chromaticity diagram. It is noted that many parameters, especially the diameter and shape of the silver nanoparticles, influence the colour of the fibre obtained.