Desizability of the Grafted Starches Used as Warp Sizing agents

An attempt is made to examine the effect of the consitituent units in the branches grafted onto the backbones of starch on the desizability of grafted starches for warp sizing. The starches investigated include starch-g-polyacrylamide, starch-g-poly(acrylic acid), starch-g-polyacrylate, and starch-g-polymethacrylate, which are synthesized via graft copolymerization in water using Fe2+-H2O2 initiators. The desizability is evaluated by enzyme, alkali, and oxidant desizings in terms of desizing efficiency, water swellability of starch film, and the time for breaking the starch film in water. It is found that the constituent units play an important role in desizability. Hydrophilic units are superior to hydrophobic ones in improving desizability. For the (meth)acrylate units, the increase in the number of carbon atoms in alkyl esters and the presence of -methyl show adverse impact on desizability. An increase in the grafting ratio of starch-g-polyacrylamide favors improvement of the desizabity whereas the increase in the ratio of starch-g-poly(methyl acrylate) reduces the desizabity. Of the three desizing methods considered here, oxidant and enzyme desizings have superior desizability to alkali one.