Study On Preparation And Properties Of Dyeable PMIA Fiber

PMIA Fiber is an excellent fire-retardant and heat-resistant fiber with satisfactory overall physical properties,harsh environment resistance and excellent machinability,which is the first choice for the high temperature protective clothing,such as the protective clothing of flammable and explosive places.PMIA Fiber used in clothing will be dyed in a variety of colors,however,the molecular structure of PMIA Fiber is close and the crystallinity?the orientation degree and the vitrification temperature are high.The small molecular dyes are difficult to enter the interior of the fiber macromolecules and it's dyeability is poor.At present,the domestic commercial PMIA Fiber is through prespinning and the color of coloring fiber is limited,which can not be woven after dyeing and flexibly respond to the customer's color requirements or small batch demand.Therefore,it is urgent to adopt an effective modification method to prepare dyeable meta-aramid which has excellent thermal stability and dyeing performance.In this paper,the wet spinning process of dyeable aramid fiber was mainly explored,the PMIA slurry was modified by using montmorillonite and hyperbranched polymer modifier,and prepared modified PMIA film,the effects of modifiers on the dyeing properties of PMIA film were discussed,and the wet spinning process and dyeing properties of dyeable aramid fiber were studied.Firstly,the PMIA solution used as raw material and DMAc used as a solvent,the PMIA film was prepared by the solution phase inversion method.The modified PMIA film was prepared by blending nano organic modified montmorillonite(MMT)and hyperbranched polymer(HBP)with PMIA solution.The dyeing properties and cross section morphology of the film were studied by changing the amount of the modifiers.The results showed that the amount of montmorillonite increased from 1% to 3%,the dye take of cationic blue dye and disperse yellow dye increased continuously.When the content of montmorillonite was 3%,cationic blue dye's dye take increased from 39.62% before modification to 58.50% after modification,and the dye take of disperse yellow dye increased from 37.42% before modification to 54.18% after modification.Three hyperbranched polymers were selected to modify PMIA.The addition of addition of carboxy terminated hyperbranched polyester(EHBP),hydroxy terminated hyperbranched polyester(HTHP)and hyperbranched aromatic polyamide(HPN)of 10% on the dyeing properties of the modified PMIA film had been studied.EHBP had a significant effect on the dyeing properties of PMIA film.When the content of was 10%,the dye take of cationic blue dye increased from 41.78% before modification to 97.94% after modification and the dye uptake increased by 134%;the dye take of disperse yellow dye increased from 37.42% before modification to 51.64% after modification and dye uptake increased by 38%.When the amount of EHBP heat treated was 10%,the dye uptake of cationic blue dye was 96.68%,and the heat treatment had little effect on the EHBP.Secondly,the dyeable PMIA fiber was made by PMIA/10wt% EHBP slurry.The rheological properties,spinnability,mechanical properties,chemical structure,thermal stability,glass transition temperature and dyeing properties of PMIA/10wt% EHBP modified slurry were studied.The results showed that,The non Newton finger value of the modified PMIA/10wt% EHBP slurry increased and or the structural viscosity decreased(??)decreased,so that the spinnability got well.When the concentration of solvent DMAc in the coagulation bath was 55%,the strength of the modified primary fiber was the best.In the drawing process,the optimum nozzle drawing rate was-0.5~-0.6,and the optimum wet draw ratio was 2.0,and the hot stretching temperature was 300?.For the infrared analysis of modified fibers,new peaks appeared at 1723 cm-1,1165 cm-1 and 1067 cm-1,indicating the presence of ester groups in the modified fibers,and EHBP was successfully added to the PMIA/10wt% EHBP modified fiber,the thermal property of PMIA fiber and PMIA/10wt% EHBP modified fiber was similar,what's more,the Tg of PMIA/10wt% EHBP modified fiber reduced by 5.99? and the crystallinity decreased by 12.97%.When the dyeing temperature increased from 100? to 130? and dyeing with cationic blue dye,the dyeing rate of PMIA/10wt% EHBP modified fiber and PMIA fiber increased.When the dyeing temperature was 130?,and the mass fraction of the dye was 1%,the dye uptake of PMIA/10wt% EHBP fiber increased by 32.98%,and the K/S value increased from 2.73 before modification to 5.57 after modification.Under the same dyeing conditions,the dye-uptake and K/S value of PMIA/10wt% EHBP modified fiber were higher than that of Dupont dyeable fabric.After washing,the K/S value of Du Pont easy-dyeing fibers is greater than that of PMIA/10wt% EHBP modified fibers,both of which are higher than PMIA fibers and the dyeing properties of modified fibers are improved.The modification will not affect the extreme temperature resistance of the PMIA fiber,the modified PMIA fiber has excellent thermal stability.