Relationship between the molecular structure, molecular polarities and dyeing properties of benzisothiazole dyes containing multi-ester groups for PET fabric

Dynamic Diffusion of Disperse Dye in a Polyethylene Terephthalate Film from an Infrared Spectroscopic Perspective

“…As for ν ar (CC) (DR 9), the frequency shift might be because of the dispersion of DR 9 during the diffusion process. − Meanwhile, during the diffusion process, it is observed that the diffusion of DR 9 through the PET film starts at around 800 s and reaches the equilibrium at almost 6500 s. By comparing the ATR–FTIR spectra collected at 800 and 6500 s in the region of 1680–1550 cm –1 during the diffusion process at 140 °C, it can be seen that ν­(CO) of DR 9 shifts toward higher wavenumbers, while δ­(N–H) of DR 9 shifts toward lower wavenumbers; in other words, the intramolecular hydrogen bonds of DR 9 are weakened after diffusion. ν ar (CC) (DR 9) shifts to lower wavenumbers, which could be because of the π–π interactions between DR 9 and PET. − In addition, ν­(CO) (PET) moves slightly toward the higher wavenumber as the diffusion process deepens (Figure b), which may be attributed to the dipole–dipole interaction between CO (DR 9) and CO (PET) .…”

Novel dispersant‐free disperse dyes containing polyethylene oxide moieties: Synthesis and eco‐friendly dyeing on polyethylene terephthalate fabrics

“…Quantum simulations of designed dyes were performed by Gaussian 16 programs. 5 Optimized geometries of azobenzene and related molecules were simulated at the B3LYP/6-31G (d) level. Electrostatic potential energy diagrams (ESP) were achieved with optimized molecular structures.…”

“…Dispersants is the indispensable component of commercial disperse dyes 1,2 . The addition of dispersants is helpful to ensure dyes dispersed in water phase uniformly, 3,4 which is beneficial to optimize the levelness and fastness properties of dyed fabrics, as well as reduce dyeing default caused by irregular distribution of dye bath 5,6 . There is no affinity between dispersants and polyethylene terephthalate (PET) and the dispersants would be discharged with effluent as second pollution 7,8 .…”

Synthesis of Benzisothiazole–Azo Disperse Dyes for High Resistance to Alkaline Treatments and Peroxide Bleaching of Polyester and Polyester/Cotton Fabric

“…The conventional production of polyester and polyester/cotton blended fabrics involves multistep wet processing, which is often operated in separate baths because of varying production conditions . For example, polyester fabric requires alkaline pretreatment, and the residual alkali on the fabric must be completely neutralized with acid reagents and rinsed with a large amount of water before it is dyed with disperse dyes under acidic conditions. , Polyester/cotton blended fabric requires an even more complicated production process including, in turn, bleaching of cotton with alkaline hydrogen peroxide, dyeing of polyester with disperse dyes, and dyeing of cotton with reactive dyes, , which must be completely neutralized and rinsed at the end of each process step, otherwise the production quality will be impaired at the next process step . Especially, when the polyester fabric is dyed with disperse dyes under acidic conditions, oligomers such as ring-trimers migrate from polyester to deposit on the fabric detracting from the dyeing quality. , Therefore, the conventional production of polyester and polyester/cotton blended fabric is featured with high consumption of energy and water. − …”