Preparation And Properties Of Highly Effective Dispersants With Comb-like Polycarboxylate Used For Disperse Dye

Since disperse dyestuff is insoluble in water,it is difficult to disperse evenly in water.Moreover,the dyestuff particles are easy to gather together,which brings about many trouble to dye the fabrics.In order to improve the dyeing property,appropriate amount of dispersant is usually added in the dyeing system,so that the dyestuff particles can be evenly dispersed and kept in suspension stable.However,there are still many problems,such as poor adsorption of dispersant on the surface of dyestuff,easy shedding and precipitating,without a stable spatial resistance effect of dispersant,low dyeing rate,and more dispersant in the dyeing waste solution,which is not friendly to the environment.Therefore,it is urgent to synthesize new and efficient dispersants to improve the dispersion performance of disperse dyes.Comb-type polycarboxylate dispersants can adsorb on the particle surface with multiple points by means of strong site-resistance effect and good dispersion performance.As a result,they are widely used in various fields.In this paper,styrene（St）,acrylic acid（AA）and maleic anhydride（MA）as copolymerization reaction monomers were selected to prepare St-AA-MA copolymer.Then,the St-AA-MA copolymer was modified by using polyethylene glycol（PEG）with different molecular weights to obtain an amphiphilic comb polycarboxylate polymer dispersant.The effects of different n（St）,n（AA）and n（MA）on the St-AA-MA copolymer and the effects of different n（St-AA-MA）: n（PEG）on the dispersion effect were compared and discussed in detail.The structures of St-AA-MA copolymers and St-AA-MA-PEG comb-like modified polymers were tested and characterized.The differences in surface properties,including dissolution properties,emulsification properties,rheological properties,surface tension,foaming and stabilization properties,wetting properties,and chelating and dispersing properties of dispersants containing different branched St-AA-MA-PEG comb structures was investigated respectively.Moreover,the effects of branched chain length and grinding conditions on the dispersion performance of comb-type polycarboxylate dispersants were studied item by item.The dyeing solution with comb-type polycarboxylate dispersants was used to dye pure PET fabric.Furthermore,the dyeing performances were also examined.It is found that when the molar ratio of monomers was n（St）: n（AA）: n（MA）=1:1:1 and n（St-AA-MA）: n（PEG）=1:3,the best dispersion effect of the synthesized St-AA-MA-PEG comb-like dispersant was implemented.The results of surface property test showed that there was a correlation between the branched chain length and the surface properties of St-AA-MA-PEG comb-like dispersant.After grinding with C.I.Disperse Orange 30 at m（St-AA-MA-PEG）: m（C.I.Disperse Orange 30）= 1:5,the alkali-treated St-AA-MA-PEG 600,namely with a branched chain molecular weight of 600,revealed the best dispersion effect.When the amount of dispersant was20 wt.% and being milled for 10 h at p H=7,the average particle size of resulting disperse dye particles was only 256.2 nm and the Zeta potential on the surface of dye particles was-41.5 m V.After centrifuging at 2000 r/min for 15 min,the centrifugal stability R of the dye solution was up to 73.38%.Moreover,the dye solution was heated at 60 °C for 1 h,the particle size change rate of the dye particles was only 0.12%.The disperse dye solution containing St-AA-MA-PEG600 was applied to dye polyester fabric by high temperature and high pressure dyeing method.It is shown that the dyeing rate was as high as 99.87% of 5% owf.It is proved that St-AA-MA-PEG600 can reduce the residue of dye and dispersant in dyeing wastewater compared with traditional dispersants silok7099 and NNO.In conclusion,the highly efficient dispersant of comb polycarboxylate prepared in this paper is expected to be used in practical production,and shows good dyeing performance.