Optimization of nano TiO2 pretreatment on free acid dyeing of wool using central composite design

Abstract

The aim of the research is to investigate nano technique of wool acid dyeing without the presence of acid auxiliary agent at temperatures lower than the boiling. The wool fabrics are first pretreated with nano TiO2 and BTCA at different concentrations. The dyeing process is then carried out on the pretreated fabrics with C. I. Acid Blue 113 and C. I. Acid Black 3 dyes. Also, the central composite design analysis is applied to design the relation between nano TiO2 and BTCA concentrations, and dye exhaustion. The response surface methodology is also applied to find the optimum conditions for the wool fabric pretreatment. The scanning electron microscopy and X-ray diffraction are employed to indicate the presence, crystal type and size of TiO2 nanoparticles on the wool surface. The pretreatment optimization on the wool surfaces considerably enhances the absorption of acid dyes. The suggested method demonstrates the improvement of fastness properties than control dyeing and could be introduced as a new route, disclosing various desirable multi-functional characteristics, to wool fabric. This technique is also free from some of the disadvantages of acid chemical involved in dyeing such as damage to wool fabrics than wool conventional dyeing.