Naphthoquinone disperse dyes and their dyeing application to polyethylene terephthalate fabrics

Chromaticity of Gromwell, Cape jasmine Dyeing, and Effects of Zinc Oxide/Polyphenol Treatment with Copper Mordanting for UV Protection

“…In Figure 5b, the peak of the yellow-dyed samples appeared at approximately 450 nm, which was slightly shifted towards 420-430 nm, where the yellow color is usually absorbed. This phenomenon can be attributed to the bathochromic effect, as mentioned in other studies [23,46]. The lowest reflectance with the highest absorbance was seen in the yellow-dyed samples of 41C and 42P samples without the UV protective treatments in this study.…”

“…In contrast to the aforementioned reflective curves, Figure 6 illustrates the CIELAB colorimetric parameter K/S values. The K/S values represent the color depth or concentration after dyeing, which were related to the molar absorption coefficient from the Beer-Lamber law and the auxochrome groups [23]. Overall, dramatic changes in colorimetric parameters were more prominent in the dyed cotton than in the dyed polyester.…”

“…Trans-isomers of chromophores in natural dyes can be converted to cis-isomers when absorbing light irradiation of a short wavelength, resulting in the discoloration of the dyed textiles [22]. Naphthoquinone, one of the quinonoid compounds, comprises many isomers, such as alkannin, lawsone, juglone, lapachol, plumbargin, and shikonin [23,24]. La and Giusti investigated the photochromism of delphinidins in anthocyanin dyes between trans-and cis-acylated isomers that were induced by visible UV light reversibly [25].…”