Room-temperature bleaching of cotton fabrics with chitosan-metal complexes/H_2O_2

Coordination of chitosan with metallic ions Cu2 + and Zn2 + was carried out in very thin solution,two kinds of chitosan-metal complexes were formed.The dynamics of catalytic decomposition of the complexes on H2O2 was investigated and room temperature bleaching of cotton with chitosan-metal complexes was performed.The result indicated that chitosan-metal complexes have excellent ability of catalyzing and decomposing H2O2 and the decomposition rate followed the first order reaction dynamics.pH value,initial concentration of complexes were the dominating factors affecting the catalytic ability of chitosan-metal complexes.The optimized conditions for catalysis by CTS′-Zn(Ⅱ) were CTS′-Zn(Ⅱ) 3 g /L and pH = 11.The optimized conditions of catalysis by CTS′-Cu(Ⅱ) were CTS′-Cu(Ⅱ)3 g /L and pH = 8.The whiteness of this low-temperature bleached fabric was similar to that by traditional process,and its strength retention was over 90%.