Study On Cation Modification Of Aramid Fiber And Its Dyeing Properties With Anionic Dyes

Aramid fiber has excellent performance and wide application,but its development was limited by its tight structure and difficult dyeing.Therefore,it was significant to study the dyeing properties of aramid fiber.Generally,aramid fibers were dyed with cationic dyes or disperse dyes under high temperature and pressure,while anionic dyes are rarely used to dye aramid.The cationic modification of aramid and the dyeing property of the anionic dye were studied in this paper.The purpose of this study is to expand the range of dyestuffs for aramid fiber dyeing and further promote the wide application of aramid fiber.Firstly,It were researched that the optimization synthetic process of cationic deepening agent through gelatin and WLS which was made from laboratory under certain conditions,and cationic depth increasing agent were analyzed by characterization and analysis of the structure and properties.The results showed that the cationic deepening agent had the structure of quaternary ammonium salt and it was cationic.It was applied to the modification of aramid fabric in this study.The process modified conditions of aramid fiber were evaluated by the species and dosage of puffing agents,the dosage of cationic softener deep agent,the dosage of sodium hydroxide,modified temperature and time through the dyeing percentage and dyeing fabric apparent color depth value.The optimal process conditions of soaking puffing modified aramid were as follows: scouring agent was 0.2% owf,JFC was 1g/L,CWP-N swelling agent was 30g/L,Cationic deep dyeing agent was 20% owf and sodium hydroxide was 4g/L and keeping liquor-to-material ratio at 20:1.Aramid fabric would be put into the fluid,and the start modified temperature was 50?.Then the processing bath was heated to 100?slowly after holding the temperature at 100? for 40 min,and then dried.The steam modified process were as follows: scouring agent was 0.5g/L,expansion agent CWP-N was 40g/L,Cationic deepening agent was 30g/L,sodium hydroxide was 6g/L,and the processing bath was heated to 50? for 20 min keeping liquor-to-material ratio at 20:1,then through110? steam 5 min.Secondly,the dyeing properties of the reactive dyes and VAT dyes for the modified aramid fibers were studied,and the optimum dyeing conditions were obtained.The optimum process of reactive dyeing were as follows: reactive turquoise blue KNG dyeswere used,keeping liquor-to-material ratio at 20:1.The dyeing bath was heated from 50~60? to 100? slowly,holding the temperature at 100? for 20 min,and then adding sodium hydroxide 1~3g/L,dyeing 20 min again,then baking,soap washing and drying.And the optimum process of VAT dye dyeing were as follows: when the dosage of dye was 4% owf,sulfur dioxide urea dosage of was 5g/L,the dosage of sodium hydroxide was 15g/L,bath ratio was 20:1,the dye was reduced at 60? for 15 min,then modified aramid was added,and dyed at 70? for 30 min,then the air oxidation was 30 min,the final post-treatment was soap washing.The dyeing effect of modified aramid fiber was evaluated.The results showed that the properties of the expanded aramid fabric to reactive and VAT dyes were significantly improved,the K/S value was clearly improved,and the color fastness of the modified aramid fabric to soaping was better,but the color fastness to rubbing was worse than unmodified aramid.The initial dyeing rate of the modified aramid fiber dyed with these anionic dyes was significantly improved,because the affinity of modified aramid fiber to reactive dyes and VAT dyes was obviously increased.But the immutability and the leveling property were deteriorated.In order to solve the problem of poor color fastness to rubbing of the modified aramid fabric,the effect of adding calcium chloride in the process of modification and adding fixing agent after dyeing of the modified aramid fabric were studied.The results showed that the rubbing fastness of dyed aramid fabric can be improved about half a stage.Then,the change of structure and properties of modified aramid fibers,and the dyeing kinetics and thermodynamic properties of reactive dyes were studied,and the relevant thermodynamic parameters were calculated.The results showed that the modified aramid fiber had cationic groups and its thermal stability was declined.The experimental data were analyzed by the quasi-first-level kinetics model and the quasi-secondary kinetics model.The results showed that the dyeing process of the modified aramid fibers dyed with reactive dyes conforms to the quasi-secondary kinetics model.The adsorption isotherms of the modified aramid fibers dyed with reactive dyes were fitted and analyzed.And it was suitable for Langmuir adsorption,and the chemical orientation adsorption was the main one.Finally,the force between modified fabric and reactive dyes was discussed.Choice of reactive dyes and acid dyes dyeing of modified aramid,and it was found the dyeing of reactive dyes after alkaline solid color,and the K/S value after soaping was higher than without fixation,and the K/S of the fabric was lower when the acid dye was added alkalior not.The comparison shows that there are some covalent bonds between reactive dyes and modified aramid fibers in addition to electrostatic attraction,van der Waals force and hydrogen bond binding force after dyeing.The one bath dyeing effect of reactive dyes on modified aramid / cotton blended fabric was studied.The results showed that it was difficult to get the same color in one bath dyeing of modified aramid / cotton blended fabric with reactive dyes,but it was expected to obtain new products with multi-color effect.There are 22 figures,50 tables and 82 references.