Research On Application Of Chitosan Derivative In Wash-Off Reactive Dyeing

Chitosan was chemically modified in different ways to probe their properties when used in soaping agents for reactive dyeing.The experiments showed that chitosan derivations(N, O-CMCTS & NAOC)could remove effectively the loose color in the reactive dyeing to increase the soaping effect in reactive dyeing.Both of N,O-CMCTS and NAOC had good water-solubility and resistance to hardness of water.The first work of this paper is measuring physical properties of chitosan.Degree of deacetylation(DD)of chitosan determined by acid base titration is about 83%.The MW of chitosan by viscometry is about 1.0×10~5.The effect between chitosan derivatives and hydrolyzed reactive dyes was also studied.The result showed that the stability of micelles composed by NAOC and hydrolyzed reactive dyes was sensitive to its concentration.The soaping effect of both derivatives could hardly be affected by increasing their concentration due to the balance between chitosan derivatives and hydrolyzed reactive dyes.At the same time the conditions affect on the soaping effect of N,O-CMCTS and NAOC,such as the existence of inorganic salt and alkaline, complexation with anionic/nonionic surfactants,have been discussed in detail.The result shows that NAOC had stronger salt-resistance than N,O-CMCTS;the complexation of N, O-CMCTS/NAOC and nonionic surfactant had slightly better soaping effect than that when used separately;while the soaping effect of NAOC was remarkably removed by complexation with anionic surfactant.At last,the concentration of chitosan derivatives,the soaping temperature,time,and pH,et al.were studied when used in soaping agents for reactive dyeing respectively.On the base of experience of above experiment,the reaction conditions of chitosan derivations were systematically investigated through orthogonal design,and then the best conditions were found.N, O-CMCTS:0.50 g/L,90℃,20min,pH=10;NAOC:0.250 g/L,90℃,20min, pH=9.Compared with one of market soaping agents,N,O-CMCTS and NAOC could raise the friction degree and soaping degree by about 0.5 degree.