Low-salt dyeing of cotton fabric grafted with pH-responsive cationic polymer of polyelectrolyte 2-(N,N-dimethylamino)ethyl methacrylate

In this work, a pH-responsive polyelectrolyte 2-(N, N-dimethylamino) ethyl methacrylate (PDMAEMA) was grafted onto the cotton fabric by surface-initiated atom transfer radical polymerization by activator regenerated electron transfer (SI-ARGET ATRP). Then, the grafted cotton fabric was dyed by reactive dyes. SEM, XRD, FT-IR, TGA and whiteness test were investigated to characterize the PDMAEMA grafted cotton fabric. Meanwhile, the dyeing temperature, fixed temperature and pH value in the dye bath were carried out to explore the optimum dyeing process. Finally, the mechanism of salt-free dyeing of PDMAEMA grafted cotton fabric is proposed. The results showed that the cotton fabric was successfully grafted by PDMAEMA, which presents excellent dye uptake, fixation yield, K/S value and dyeing uniformity and color fastness under the dyeing temperature of 30 degrees C, the fixed temperature of 60 degrees C,and the pH value of 6. Moreover, the pH-responsive process not only realizes saltfree dyeing, but also increases the dye up-take, fixation yield and the dye levelness due to the migration dyeing process. This work provides a promising route to realize the salt-free dyeing of reactive dye on cotton fabric, which is beneficial to environment protection for the significant reduced content of dye and salt in waste water.