Study On The Cationically Grafted Starch Of Quaternary Ammonium Salts As Sizing Agents

At present, most research papers of grafted starch were concentrated in vinyl monomersin the field of sizing agent, such as acrylic acid, acrylate and acrylamide, et al. The commoncharacteristic of this kind of grafted copolymer was that the zeta potential was negative in thewater. As we all known, the ζ potential of polyester fiber and cotton fiber in water is negativeand it can be imagined that the same charges lead to repulsion at adhesive layer/fiberinterfaces, and may adversely influence the adhesion to fibers. In order to improve theadhesion force of fiber, we introduced the cationically branched chain of quaternaryammonium salts into the starch molecule, and further improve the use ability of starch.Therefore, this paper explored two kinds of cationically grafted starch of quaternaryammonium salts as sizing agents. The first part of paper studied the properties ofstarch-g-poly （methacryloxyethyltrimethyl ammonium chloride）（St-g-PDMC）, proved thatthis cationically grafted starch of quaternary ammonium salts could be used as sizing agent.Then use acryloxyethyltrimethyl ammonium chloride （ATAC） as grafted monomer, prepared aseries of starch-g-poly （2-acryloyloxy ethyl trimethyl ammonium chloride）（St-g-PATAC）with different grafting ratio, analyzed its structure and in-depth studied effect of grafting ratioon the properties of St-g-PATAC.To examine the end-use ability of St-g-PDMC, the graft copolymerization of starch withmethacryloxyethyltrimethyl ammonium chloride was initiated by using Fe²⁺-H2O2redoxsystem for preparing a series of St-g-PDMC with different grafting ratio （GR）. The influencesof GR on the viscosity stability, ζ potential and adhesion to fibers were studied.Theexperimental results showed that the starch grafted with DMC could enhance the adhesion ofgrafted starch to fibers by electrostatic interaction between positive and negative charges, andfurther improve the use ability of grafted starch during warp sizing operation. Consideringviscosity and viscosity stability, ζ potential, adhesion to fibers, the St-g-PDMC with a7.9%value in GR was preferred.To further examine the end-use ability of the cationically grafted starch of quaternaryammonium salts, Fe²⁺-H2O2redox system was used as initiator, synthetized a series ofstarch-g-poly（2-acryloxyethyltrimethyl ammonium chloride）（St-g-PATAC） with differentgrafting ratio （GR） and analyzed its structure. The influences of GR on the viscosity andviscosity stability, film properties, ζ potential, surface tension, cantact angle and adhesion tofibers, biodegradability and desizing efficiency were studied. The experimental resultsshowed that the starch grafted with ATAC, the crystallinity of starch decreased, thermalstability got better, viscosity of starch cooked paste increased and viscosity stability becamewell, the mechanical properties of film got better, time required to break the film in waterdecreased, moisture absorption, the swelling and dissolution of film increased, ζ potential alsoincreased with the increasing of grafting rate, surface tension, cantact angle and adhesion tofibers initially increased fast and then slow-growth, the value of BOD5/COD ratio reducedand desizing efficiency decreased with the increased of grafting rate. The appropriate ofgrafting ratio should be7.5%after taking the experimental results into overall consideration.