Research On The Preparation Of Grafted Starch Sizing Agent Based On ARGET ATRP Technology And Properties

Starch as one of the most abundant polysaccharide polymers,has been widely used in the textile field,since it possesses good biodegradability,environmental friendliness,and so forth.However,natural starch exhibits poor resistances to shearing and high temperature,leading to rigid and brittle film formed from starch paste.In addition,starch has low water-dispersibility,which can produce a negative impact on the wetting and spreading of starch paste on the fiber surfaces,and is not conducive to the adhesion between starch and fibers,thereby limiting its practicality.To improve the properties of starch size and provide a new type of grafted starch size for warp sizing,grafted starch（BBES-g-PAA）was prepared by activator regenerated by electron transfer of atom transfer radical polymerization（ARGET ATRP）using acrylic acid（AA）as monomer and 2-bromoisobutyl esterified starch（BBES）as starch-based macroinitiator.Its synthesis parameters were studied,and then based on the suitable synthesis process parameters,a series of BBES-g-PAA samples were prepared and their sizing properties were investigated.The suitable synthesis parameters of BBES-g-PAA with ARGET ATRP system were obtained:reaction temperature of 40^oC,1.2 in the molar ratio of vitamin C（VC）to BBES,0.32 in the molar ratio of Cu Br₂ to BBES,0.6 in the molar ratio of PMDETA to BBES,and reaction time of 5h.According to the parameters,several BBES-g-PAA samples with the grafting ratio range of4.63%to 14.14%were successfully prepared.Compared with AHS and BBES,BBES-g-PAA displayed higher adhesion to wool fibers,and the adhesion increased as increasing the grafting ratio.Compared with AHS and BBES starch films,BBES-g-PAA starch films had higher elongation at break and lower tensile strength.XRD analysis of the films and SEM characterization of the tensile cross-section of the starch films confirmed that the graft modification provided a positive effect for reducing the starch film brittleness.Secondly,in order to further explore the influence of amphipathic graft polymerization on the properties of starch paste,in this subject,AA and butyl acrylate（BA）were used as graft monomers to prepare the amphipathic graft polymerization starch[BBES-g-P（AA-co-BA）].BBES-g-P（AA-co-BA）samples were successfully prepared by ARGET ATRP system under the condition that the ratio of AA and BA monomers（molar ratio of AA and BA was 73:27）was kept constant,and the effects of amphipathic graft polymerization on the adhesion of starch samples,tensile properties of the starch films and sizing properties of starch paste were investigated.The findings:Compared with AHS and BBES paste,the viscosity thermal stability of BBES-g-P（AA-co-BA）paste is higher than90%,which meets the requirements of warp sizing.Moreover,the adhesion of BBES-g-P（AA-co-BA）paste to polyester fiber and polyester/cotton fiber is significantly improved.Compared with AHS and BBES starch films,BBES-g-P（AA-co-BA）starch films have lower crystallinity,lower water dissolution time,and stronger toughness.Finally,BBES-g-P（AA-co-BA）（VI）,AHS and BBES samples with a total graft ratio of 16.51%were selected to conduct sizing experiments on polyester and polyester/cotton blended yarns,and sizing properties were tested and analyzed.The results show that BBES-g-P（AA-co-BA）（VI）has21.8%enhancement rate,15.2%elongation reduction rate,144%wear increase rate and 87.2%hairiness reduction rate after sizing polyester and polyester/cotton blended yarn.The enhancement rate,elongation reduction rate,wear increase rate and hairiness reduction rate of polyester/cotton blended yarn are 23.7%,16.3%,169%and 84.1%respectively.Compared with AHS and BBES sizing,the properties of BBES-g-P（AA-co-BA）（VI）sizing have been improved to a certain extent,and the developed new sizing can obviously improve the sizing properties of the two warp yarns.