UV protection properties of silk fabric dyed with eucalyptus leaf extract

A natural dye extracted from eucalyptus leaves was applied to a silk fabric using two padding techniques, namely the pad‐batch and pad‐dry techniques, under different conditions. It was observed that with an increase in the dye concentration, the ultraviolet (UV) protection factor (UPF) values ranged between good and excellent for the silk fabric. In addition, a darker colour, such as that provided by a FeSO₄ mordant, gave better protection because of higher UV absorption. A silk fabric dyed in a solution containing the eucalyptus leaf extract showed a shade of pale yellowish‐brown. The exception was when the fabric was dyed with the FeSO₄ mordant, resulting in a shade of dark greyish‐brown. The colour fastness to washing and rubbing of the silk fabrics treated with the mordant after dyeing was investigated and the results showed good fastness, whereas colour fastness to light was at a fair level. The results confirmed that natural dyes from eucalyptus leaf extract with metal mordants have potential applications in fabric dyeing and in producing UV‐protective silk fabrics.     

Dyeing of Cationized Cotton with Natural Colorant from Purple Corncob

In this investigation, dyeing of cotton fabric with natural dye extracted from purple corncob was attempted by means of pretreatment with a cationic agent, 3-chloro-2-hydroxypropyltrimenthylammonium chloride (CHTAC). Maximum color yield results were achieved when the fabric was pretreated with CHTAC at a concentration of 125 g/L, followed by dyeing at 100°C for 30 min in a dye bath adjusted to pH 9. The influence of meta- and post-mordanting with AlK(SO₄)₂, CuSO₄, FeSO₄, and gallnut was subsequently explored. Compared with the unmordanted sample, post-mordanting enhanced K/S values and slightly improved light fastness, but both meta- and post-mordanting caused a reduction in wash fastness from an excellent to a fair level, with the exception of CuSO₄. Meanwhile, mordanting with gallnut increased the acid and alkaline perspiration fastness from a poor and fair to a good level.     

Ecological dyeing of silk fabric with lac dye by using padding techniques

This research focuses on silk fabrics exhibiting different colour values and fastness properties. The samples were prepared by dyeing with lac as a natural colourant. Two padding techniques were used in the process, namely, the pad-batch and pad-dry techniques, under different conditions. Aluminium potassium sulphate, ferrous sulphate, copper sulphate and stannous chloride were used as mordants. The effects of differing dye concentrations added to the silk fabrics using a pre- and post-mordant method were studied and recorded. The colour fastness to washing, light, rubbing, water and perspiration of the dyed samples was performed according to the present ISO standard. Silk fabric dyed without mordant showed a pink shade, while those samples mordanted with stannous chloride and aluminium potassium sulphate displayed noticeably brighter red coloured shades. With the additional use of copper sulphate, the colour shade produced was violet, while darker grey shades were obtained by adding ferrous sulphate mordant. The test results regarding fastness properties ranged from fair to very good, while wash fastness ranged from very poor to poor.