Dyeing Properties Study Of Electrospun Polyacrylonitrile Micro-nanofibers

In recent years,textile fabrics have become the trend of high grade and functionalization.People pay more and more attention to the comfort of textiles and the functional requirements.For example,functional textiles such as waterproof,breathable,anti-bacterial and UV-resistant fabrics are getting more and more sought after.Another category are the micro-nanometer fiber materials for their unique size effects during application in functional textiles.With the development of electrospinning technology,the nanometer-scale fiber materials prepared through this technology are being given more and more attention for use in the field of traditional textiles.In addition,these nanomaterials are revolutionizing sensing,filtration and biomedical fields.Combining electrospinning with the traditional textile technology to produce functional textiles has become possible.However,if these textiles are to remain with the mentioned application markets,dyeing is of particularly importance.At present,little research has been done on the dyeing properties of electrospun micro-nanofibers and their blends with traditional fibers,which limits their market share.When the size of fibers gets smaller,existing dyeing processes face fresh challenges.Therefore,in this paper,polyacrylonitrile(PAN)with the reputation of "artificial wool" was spun into micro-nano fibers through the electrospinning process,and PAN micro-nanofiber/cotton blended knitted fabric was prepared by combining this technology with traditional textile technology.Firstly,the physical structure of PAN micro-nanofibers was characterized by FTIR,XRD,DSC and SEM.The results showed that PAN micro-nanofibers have basically the same chemical composition as the conventional PAN fine fibers,and the supramolecular order is not significantly different from that of the spinning mode.The crystallinity and the glass transition temperature of PAN micro-nano fibers were slightly lower than those of PAN fine denier fibers.The results showed that the basic dyeing performance of PAN micro-nanofibers was similar to that of PAN fine fibers.However,the initial dyeing rate was high,and the addition of ?-cyclodextrin had a good retarding effect.After dyeing,the apparent color yield of PAN nanofibers was low,but their morphology and tensile properties were well maintained and their color fastness was better.Secondly,in order to deeply understand the dyeing mechanism of PAN micro-nanofibers,their dyeing kinetics and thermodynamics were analyzed.The results showed that PAN micro-nanofibers closely followed the quasi-second-order kinetic model,and the relevant kinetic parameters of dyeing were calculated accordingly.The results indicated that the equilibrium adsorption quantity,dyeing rate constant and the diffusion coefficient increased with increasing temperature,while the half dyeing time decreased.The thermodynamic model of dyeing is in accordance with the Langmuir isothermal adsorption model and belongs to the single-layer chemical orientation adsorption.The thermodynamic parameters were calculated by this model and the results showed that the theoretical saturation adsorption capacity and empirical adsorption equilibrium constant increased with the increasing temperature.Then,the same color of PAN micro-nanofibers and cotton knitted fabrics was investigated using the monochromatic method.Different types of reactive dyes were selected for cotton dyeing based on PAN micro-nanofiber color characteristic values.Depending on this,the best dyeing process for the PAN micro-nanofiber/cotton blended knitted fabric(which was prepared by combined the electrospinning technology with traditional carding machine)was dyed with one-bath two-step dyeing process.The results showed that the optimum dyeing conditions of PAN micro-nanofibers was as follows: dyeing concentration 4% owf.(on weight of fabric),temperature 90?,pH 4~5,time 70 min,concentration of ?-cyclodextrin 1.5 g/L.then the cotton knitted fabric was dyed with reactive dyes,the monochromatic color of the three colors was obtained at 60?,the concentration of sodium sulphate was 30 g/L,the concentration of sodium carbonate was 25 g/L,dyeing time was 2h,concentrations of the dyes were 2% owf.(Anozol RED BRE),1.5% owf.(Anozol yellow GL),and 1% owf.(Anozol blue RV)respectively.Moreover,the levelness and color fastness of the blended knitted fabric was good.Finally,in view of the differences in the choice of dye types between conventional PAN/cotton blends,it is difficult for the blends to achieve one-bath one-step dyeing with the same dye.In this paper,the cationic third monomer 2-aminoethyl methacrylate hydrochloride(AMA),acrylonitrile(AN)and methyl acrylate(MA)were synthesized by free radical polymerization to synthesize a modified PAN containing cationic groups on the macromolecular chains.Then the P(AN-MA-AMA)micro-nanofibers was fabricated by electrospinning,P(AN-MA-AMA)micro-nanofiber/cotton blended knitted fabric was prepared by combined the electrospinning technology with traditional carding machine and their dyeing properties were analyzed with reactive brilliant X-3B.The result shows that P(AN-MA-AMA)micro-nanofiber and P(AN-MA-AMA)micro-nanofiber/cotton blended knitted fabric had a good dyeing performance when used the anionic dyes(reactive brilliant X-3B),The effect of one-bath one-step dyeing on the blended fabric was found to be pretty good.