# Improving the Dyeability and Anti-Wrinkle Properties of Cotton Fabric via Oxidized Raffinose
## 3 Results and Discussion
### Anti-Wrinkle Finishing and Dyeing of the Fabrics  
The anti-wrinkle and dyeing properties of fabrics treated with oxyRa, DMDHEU, glutaraldehyde, and BTCA with the pad-dry-cure method were summarized in Table 4. No. 1, 3, 6, 9, 12 were the fabrics with anti-wrinkle finishing only. No. 2 was the fabric with dyeing only. No. 4, 7, 10, 13 were the fabrics with dyeing, and then with anti-wrinkle finishing. No. 5, 8, 11, 14 were the fabrics with anti-wrinkle finishing, and then with dyeing. From No. 1 and 3 in Table 4, it was evident that the WRA of the oxyRa-treated fabric were obviously better than reference, being 245.23\({}^{\circ}\), a 106.87% increase over the control. This was equivalent to DMDHU-treated fabrics (247.25\({}^{\circ}\)), much lower than WRA of GA- and BTCA-treated fabric (251.21\({}^{\circ}\) and 262.64\({}^{\circ}\)), which indicated that oxyRa can cross-link with the cotton fabric to impart anti-wrinkle properties to the fabric. This was because the aldehyde groups of oxyRa were combined with the hydroxyl groups of cotton cellulose to form hemiacetals or acetals, and a network structure was formed inside the fiber to reduce the relative slippage between the cellulose [12; 22; 23], thereby improving the anti-wrinkle properties of the fabric. No. 4, 7, 10, 13 were the fabrics with dyeing, and then with anti-wrinkle finishing, the anti-wrinkle performance of the finished fabric was obviously decreased compared with No. 2, and the color of the fabrics were deepened, and the k/s value increased. It can also be seen from Figure 5 that the apparent color of the fabric becomes darker. This shows the defect of the processing technology of dyeing first and then finishing, and it was also the reason we designed the anti-wrinkle first and then dye process. Figure 4: 3D surface plot for WRA with 4 factors. ((**a**) is WRA’s dynamic changes of the MgCl\({}_{2}\) and pH, (**b**) is WRA’s dynamic changes of the MgCl\({}_{2}\) and Curing Time, (**c**) is WRA’s dynamic changes of the MgCl\({}_{2}\) and Curing Temperature, (**d**) is WRA’s dynamic changes of the pH and Curing Temperature, (**e**) is WRA’s dynamic changes of the pH and Curing Time, (**f**) is WRA’s dynamic changes of the Curing Temperature and Curing Time). From No. 5, 8, 11, 14, after anti-wrinkle finishing and dyeing finishing, the difference in WRA of the four fabrics were small, but the k/s value of the fabrics dyed after oxyRa finishing was 13.88, which was significantly higher than that of the fabrics finished with DMDHEI, GA and BTCA, and the \(\Delta\)E value was the smallest. This means that after the fabric was finished with oxyRa, the color of the fabric was deeper and closer to the reference (No. 2). From Figure 5, the apparent color of the No. 5 sample was also deeper than No. 8, 11, and 14, indicating that the hydrophilicity of the fabric after DMDHEU, GA and BTCA finishing was decreased, and it was not easy to combined dyes, which made the fabric difficult to dye. It was because that there were covalent binding reactions between the crosslinking agents and the hydroxyl groups of the fibers during the finishing process, in which some of the hydroxyl groups reacted, so the number of hydroxyl groups that can form hydrogen bonds with the dye was decreased. This can be further analyzed from the combination mechanism of reactive dye, crosslinkers and fibers in Scheme 2. It would be interesting to understand the mechanism of the reactive dye and four crosslinking agents with cotton cellulose, and analyze the effects of changes in hydroxyl contents in the finishing and dyeing process (Figure 4a-e) [13, 17, 18]. From the combination mechanism that dyeing and anti-wrinkle finishing agents have a competitive relationship with the hydroxyl groups of cellulose, and the hydroxyl content of cellulose was reduced after the combination [24, 25, 26, 27].