Effect of cationic protein auxiliary on the reactive dyeing properties and structure of aramid fabric

Aramid fabric was plasticized and modified with combination of carrier CWP-N and cationic gelatin protein auxiliary. The dyeing property of the treated aramid fabric dyed with reactive dyes was evaluated. And the modification mechanism of aramid fabric and its reactive dyeing mechanism were analyzed. Then, the structures of the treated aramid fabric were characterized with Fourier transform infrared (FTIR), scanning electron micrograph (SEM), surface friction properties and X-ray diffraction analysis, respectively. In addition, the glass transition temperature and the thermal properties of the treated aramid fabric were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. The results showed that the dyeing properties of the treated aramid fabric to reactive dyes were improved highly. Compared with the untreated aramid fabric, the dye uptake of the treated aramid fabric increased by more than 2.7 times, the color depth (K/S value) after soaping increased by more than 8 times, and the dye total fixation rate increased by more than 3.2 times. The chemical structure and surface morphology of the treated aramid fabric were changed significantly. And the glass transition temperature of the treated aramid fabric was reduced. The main reason for the significant improvement of reactive dyeing properties of the treated aramid fabric was the change of its structure. However, the crystallinity of the treated aramid fabric was almost unchanged. And the thermal stability of the treated aramid fabric was reduced.