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The aim of this research is to investigate the influence of low molecular weight chitosan (LWCS) on the dyeability of cotton fabrics. Various concentrations of hydrogen peroxide were used to degrade chitosan to LWCS, which was used to pretreat cotton fabrics under different conditions in order to determine its influence on subsequent acid dyeing of the fabrics. The results showed that the molecular weight of LWCS decreased with increasing concentration of hydrogen peroxide. Additionally, LWCS pretreatment of cotton fabric is beneficial for acid dyeing. The K/S values for fabric dyeing increased with a decrease in LWCS molecular weight and the concomitant increase in concentration; a concentration of 4% LWCS yielded the best result. The anti-bacterial properties of fabrics pretreated with LWCS were better than those pretreated with chitosan. The dye and anti-bacterial fastness after 20 washes were best for fabrics pretreated with LWCS.

We modified a basic dye, which carries a positive charge, by inducing an exchange with clay, and then analysed the results by using Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The intercalation of basic dye into clay modifies the thermal properties of the dye, and the dyes become more stable as more clay is added. The colour of the modified dyes does not change with the addition of more clay, although its absorption decreases, thereby conferring improved sunlight colour fastness on the modified dyes.