Abstract
Cotton fabrics were dyed with the madder and compounds of citric acid (CA) and dicarboxylic acids [tartaric acid (TTA), malic acid (MLA), succinic acid (SUA)] as cross-linking agents and sodium hypophosphite (SHP) as the catalyst. The molecular structures and crystal structures of the dyed cotton fabrics were analyzed using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The results showed that the polycarboxylic acids esterified with the hydroxyl groups in the dye and cellulose, respectively, and the reaction mainly occurred in the amorphous region of the cotton fabric. Compared with the direct dyed cotton fabric, the surface color depth (K/S) values of the CA, CA+TTA, CA+MLA, CA+SUA cross-linked dyed cotton fabrics increased by approximately 160%, 190%, 240%, 270%, respectively. The CA+SUA cross-linked dyed cotton fabric achieved the biggest K/S value due to the elimination of the negative effect by α-hydroxyl in TTA and MLA on esterification reaction, and the cross-linked dyed cotton fabrics had great levelness property. The washing and rubbing fastness of the cross-linked cotton fabrics were above four levels. The light resistance stability and the antibacterial property of the cross-linked dyed cotton fabrics was obviously improved. The sum of warp and weft wrinkle recovery angle (WRA) of the CA+SUA cross-linked dyed cotton fabric was 55° higher than that of raw cotton fabric, and its average UV transmittance for UVA was less than 5% and its UPF value was 50+, showing a great anti-wrinkle and anti-ultraviolet properties.
Highlights
Most natural dyes are extracted from plant roots, stems, leaves, and flowers, and they are widely used in fabric dyeing due to the advantages of large reserves and rich colors [1]
Some metal ions are used as mordants to improve the surface color depth (K/S) value and color fastness of the dyed cotton fabric by madder, since the complex structures by the dye-mordant-cotton fabric make the dye be deposited on the cotton fabric in the mordant dyeing process
After the dyed cotton fabric was padded with two dips and two nips [wet pick up (80% ± 1%), the same below], and it was washed with the running tap water and dried at room temperature (20–25 ◦C)
Summary
Most natural dyes are extracted from plant roots, stems, leaves, and flowers, and they are widely used in fabric dyeing due to the advantages of large reserves and rich colors [1]. As the main pigment of madder dye, Alizarin (1,2dihydroxy anthraquinone) has a low affinity for the cotton fabric. Alizarin has active α-hydroxyl, which can form complex structures with metal ions [5]. Some metal ions are used as mordants to improve the surface color depth (K/S) value and color fastness of the dyed cotton fabric by madder, since the complex structures by the dye-mordant-cotton fabric make the dye be deposited on the cotton fabric in the mordant dyeing process. The heavy metals remain in the cotton fabric and dyeing effluent affect human skin health and cause some environmental problems [6]. In order to obtain ecological textiles, it is necessary to pursue a new eco-friendly dyeing method. In order to obtain ecological textiles, it is necess2aorfy14to pursue a new eco-friendly dyeing method.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
