Effect of Starch Dodecenylsuccinylation on the Adhesion and Film Properties of Dodecenylsuccinylated Starch for Polyester Warp Sizing

A series of dodecenylsuccinylated starches( DSSs) with different degree of substitution( DS) were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for investigating the influences of starch dodecenylsuccinylation upon the performances such as apparent viscosity and surface tension of starch paste, film behaviors,and adhesion to fibers for warp sizing. It was found that the dodecenylsuccinylation was able to reduce the surface tension of cooked starch paste and enhance the adhesion of starch to polyester fibers. It was also capable of depressing the brittleness of native starch and improving the mechanical behaviours such as breaking elongation and work-to-break of starch film. Initial increase in DS level of dodecenylsuccinylation enhanced these positive effects,while excessively increasing the level resulted in marked reduction in tensile strength of starch film and significant decrement in reaction efficiency. X-ray diffraction patterns of starch films showed the dodecenylsuccinates derivatized onto the backbones of starch depressed the degree of crystallinity of starch film. Based on the paste behaviors, adhesion, and film properties, the dodecenylsuccinylation level is recommended in a range of 0. 015-0. 025 for sizing polyester warps.

Effect of Structural Units on the Adhesion of Acrylic Copolymers to Fibers for Warp Sizing

Radical copolymerization of acrylic acid(AA)with acrylamide(AM)or acrylamide/acrylonitrile(AM/AN)was initiated with ammonium persulfate as initiator to produce acrylic copolymers such as bicopolymer poly(AM-co-AA)and tercopolymer poly(AM-co-AN-co-AA)for revealing the effects of the structural units of the copolymers on the adhesion of the copolymers to polyester or cotton fibers for warp sizing.The adhesion was evaluated in terms of tensile strength and work-to-break of a roving impregnated with the copolymer solution.It was found that the adhesion strongly depended on type and amount of the units incorporated into the copolymeric chains.Whether the fiber is cotton or polyester,the adhesion of the bicopolymer poly(AM-co-AA)is greater than that of polyacrylic acid or polyacyamide.Excessively increasing the amount of AM or AA unit in poly(AM-co-AA)lowers the adhesion.To enhance the adhesion of the bicopolymer,a favorable mole ratio of AM to AA is 70/30.Based on this mole ratio,incorporation of acrylonitrile units into poly(AM-co-AA)to form tercopolymer enhances the adhesion.

The Usability of Polyoxyethylene Stearate as Lubricant for Sizing Cotton Warp Yarns

The usability of polyoxyethylene stearate with 10 ethylene epoxides(POES 10) as lubricant in warp sizing was investigated for replacing sizing cream in order to prevent blockage of paste delivery tube.The influences of POES 10 and sizing cream upon the adhesion of starch to fibers and the performances of starch film were measured and compared.Then,the usability of POES 10 as lubricant was evaluated through the comparison between POES 10 and sizing cream in tensile behaviors,abrasion resistance,and hairiness of sized cotton yarns.The experimental observation demonstrates that the influence of POES 10 upon the adhesion is similar to that of sizing cream.POES 10 is superior to sizing cream in tensile strength and breaking elongation of starch film when mass content of lubricants is equal to or exceeds 2%.Incorporating POES 10 into starch makes starch film more resistant to wear.Furthermore,POES 10 is preferred to sizing cream in the increase in tensile strength,loss in elongation,and abrasion resistance of sized cotton yarns.Using POES 10 as lubricant in size formulation is favorable to the decrease of longer hairs on sized yarns.POES 10 exhibits potential use during cotton warp sizing for replacing sizing cream.