Adhesion to cotton and polyester fibers and film properties of starch-g-poly(sodium allyl sulfonate-co-ethyl acrylate) for warp sizing

Starch- g -poly(sodium allyl sulfonate- co-ethyl acrylate) (S- g-P(SAS- co-EA)) containing amphiphilic P(SAS- co -EA) branches, were synthesized via the graft polymerization of acid-converted starch (ACS) with sodium allyl sulfonate (SAS) and ethyl acrylate (EA) monomers in an aqueous phase, for providing a new biological starch sizing agent for warp sizing. The adhesion to cotton and polyester fibers was determined by testing the bonding forces of sized roving according to the method of FZ/T 15001-2008. The film properties were measured in terms of breaking elongation, tensile strength, and bending endurance. In the grafting ratio range of 2.82–10.62%, S- g-P(SAS- co -EA) samples with a range of 4.76–10.62% were significantly superior to ACS (grafting ratio = 0) in the bonding forces to cotton fibers, and film elongation and endurance ( p < 0.05). As the ratios increased from 7.91% to 10.62%, the S- g-P(SAS- co-EA) samples were obviously higher than ACS in the forces to polyester fibers ( p < 0.05). These results concluded that incorporating amphiphilic P(SAS- co -EA) branches could significantly promote the adhesion of starch to both fibers and reduce its film brittleness to provide higher extensibility and flexibility. With the rises in the grafting ratios from 2.82% to 10.62%, bonding forces as well as film elongation and endurance were gradually increased, whereas the tensile strength of S- g-P(SAS- co-EA) film was consistently reduced. Based on the results, the S- g-P(SAS- co-EA) possessed superior adhesion and film properties and could be used as a potential sizing agent for sizing cotton and polyester warps.