Study On Process Optimization Of Carboxymethyl Waxy Corn Starch And Its Application In Printing

Sodium alginate as a common printing paste was widely used in dyeing and printing enterprise.In recent years,with its price was gradually raised resulting to the increase of production cost.Meanwhile,the defects of this printing paste was unavoidable such as poor delicacy of high quality printing,Therefore,new printing paste with the characteristic of excellent performance,low cost and meeting high quality printing requirements was needed.In this article,the waxy corn starch with good extensibility,excellent stability,low price and wide range of sources was used as raw material.And the process parameters of synthesis of carboxymethyl waxy corn starch printing paste were optimized.What's more,the properties of the starch paste and its application performances in cotton fabrics printing with reactive dyes were further investigated.In the preparation of carboxymethyl waxy corn starch,method of combining single factor and orthogonal experiment were used,and the results were as follow: the dosage of starch was 16.2 g(0.1mol),the dosage of solvent was 3.4ml/g while total solvent concentration was 94% and ratio of solvent(ethanol: isopropanol)was 4:6,the dosage of chloroacetic acid was 0.12 mol,the dosage of alkali(NaOH added in twice with the ratio of 1:1)was 0.24 mol,the etherification time was 4.5h,the alkalization time was 60 min,the etherification temperature was 60?,the alkalization temperature was 35?.And the influence of different factors from primary to secondary on the synthesis of the starch printing paste was: solvent ratio>solvent concentration>etherification temperature>chloroacetic acid dosage>etherification time>alkali dosage>solvent dosage>alkalization time>alkalization temperature.At the same time,the properties of the carboxymethyl waxy corn starch printing paste obtained under the optimum synthesis process were tested and analyzed.TheFourier transform infrared spectrometer(FI-IR)test result shown that: the grafted of carboxymethyl functional groups resulted to the carboxymethylation of the waxy corn starch.The scanning electron microscopy(SEM)testresult shown that:waxycorn starch carboxymethylationwas through macromolecularreaction,and the structure of starch was obviously damaged,which was almost in flaked.The thermal analysis test result shown that: the thermal decomposition temperature of carboxymethyl waxy corn starch was 250?,thus the methyl group cannot be destroyed during the subsequentprintingprocess of steaming and drying.The X ray diffraction(XRD)test result shown that: after carboxymethylation,the crystal lattice structure of waxy corn starch was basically remain unchanged,but itscrystallinitywas reduced.In the physical and chemical properties test,when compared with sodium alginate paste,the carboxymethyl waxy corn starch paste possesses the properties of stronger false plasticity and high paste rate,and its viscosity(the mass concentration of the paste was 5%)can be 17000 MPa,PVI value can be 0.2989,filament dragging can be 5cm,storage stability can reach 7 days and so on.But its water holdingperformance was still poor.The carboxymethyl waxy corn starch paste was used in the cotton fabric printing with reactive dyes and the optimum printing process was determined: while the total weight of the paste was 100 grams,the printing paste concentration was 4%,the dyes concentration was 2%,the dosage of color fixing agent sodium bicarbonate was 3%,the dosage of urea was 5%,the dosage of reserve salt was 1%,steaming at 95?for10min.Comparing two kinds of paste printing results showed that:the carboxymethyl waxy corn starch paste printing fabric color was deeper and has good uniformity,the rubbing fastness of printed fabric can be reached 4-5,but the paste take-off rate and the handle of the printed fabric were still poor.In conclusion,compared with sodium alginate paste,carboxymethyl waxy corn starch pasting rate is higher and the printing paste amount can be reduced 60%,thus the amount of raw materials and cost were reduced.The carboxymethyl waxy corn starch paste had high viscosity structure,thus its fabric color was deeper compared with sodium alginate paste,and the dye amount can be saved.As the substitution degree of carboxymethyl waxy corn starch paste was increased to more than 1,the filament dragging length is higher than that of sodium alginate paste,and the PVI value is low,suitable for high quality fine pattern printing.However,because of its poor water holding,and incompletely substitution of the hydroxylin the paste molecular,the handle and paste take-off performance were still pool There are 49 figures,26 tables,63 references.