Desizability of the Grafted Starches Used as Warp Sizing agents

Abstract

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 α‐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.

Effect of pH on the physicochemical properties of 2-dimethylaminoethyl starch and its desizability

“…The removal rate of starch sized on warp yarns depends on the swelling ability of starch film, which determines the permeability of reagents in the desizing process. 26 Therefore, the swelling ability of starch films should be evaluated. According to Park's method, it was measured with some modifications.…”

“…Due to higher charge density and electrostatic force, DMAES has stronger adhesion to cotton fiber under acid conditions. Furthermore, the presence of sodium hydroxide could destroy the combination between the starch chain and fiber, 26 resulting in lower adhesion to the cotton fiber under alkaline conditions.…”

Differences in the desizability of starches and the mechanism of inhibiting desizing

“…where W s and W y are the weight of starch and the yarns, respectively. The desizability was evaluated by detecting the desizing efficiency according to the method of Liu et al, 7 with some modifications. The sized yarns were dipped in hot water (60 C) for 5 min, and then it was extruded by rolling mill to make the yarns with a weight growth rate of 80-90%.…”

“…5,6 The common methods for desizing are the treatments using enzymes, oxidants, or alkalis. 7 However, the oxidant and alkali desizings require many chemical reagents (strong alkalis and oxidants) to remove the sizes, which produces a large amount of waste water. 8,9 In addition, the reagents used in desizing can destroy the cellulose structure and cause the loss of fiber strength.…”

Development of a Novel Energy Saving and Environmentally Friendly Starch via a Graft Copolymerization Strategy for Efficient Warp Sizing and Easy Removal

“…It is well known that the warp yarn will be repeatedly subjected to a series of mechanical forces during the weaving process, so that the phenomenon of frequent breakage of the warp will result in low weaving efficiency [ 1 , 2 ], Therefore, warp sizing is a critical process in textile production, which forms a film on the surface of the yarn to improve the mechanical properties of the warp, protecting the yarn so it is not easy to break. As a renewable natural polymer compound in nature, starch has become an important textile sizing material due to its availability, low price and biodegradability [ 3 , 4 ].…”