Technological Evaluation of Nitrogen Containing Starch Derivatives as Sizing Agents

Abstract

The structural changes brought about by introducing different nitrogen containing groups via cyanoethylation, carbamoylethylation and carbamation in the molecules of rice and maize starches and oxidized starches derived thereof and the onset of these changes on the technical properties of yarns sized with such starch products were investigated. It was found that the apparent viscosity of pastes prepared from those products depends on the nature of starch, the degree of oxidation prior to chemical modification, the nature of modification as well as the measuring conditions, i. e. the rate of shear and temperature. Cotton yarns sized using these starch derivatives were measured for yarn number, tensile strength, C.V.%, elongation at break and C.V.% in elongation. Besides, the weavability test expressed as the minimum number of cycles due to abrasion (St1) and average number of cycles due to abrasion (St6) were investigated. A comparison among modified starches prepared from rice starch would reveral that the highest value of St1 is obtained with yarns sized using carbamoylethylated sample derived from unoxidized starch. With maize starch, on the other hand, the highest value of St1 is obtained with cotton yarns sized using carbamoylethylated starch derived from starch oxidized by 1 g/l active chlorine.

γ‐Radiation‐treated starch/poly(vinyl alcohol) composites for cotton fabric sizing

“…Hebeish and coworkers carried out extensive work on modifying the physicochemical properties of starches: starches were acid-treated, 5 oxidized, 6 -8 etherified, 9 and grafted by chemical methods. 10 The blending of starch with PVA 11 or poly(methacrylic acid) 12 has been also investigated for the property modification of natural starches. However, most research work on polymer blends based on starch and PVA has been directed to the preparation of biodegradable plastics for environmental reasons.…”

“…As noted, both starches and PVA cause problems in the sizing and desizing processes. Hebeish and coworkers carried out extensive work on modifying the physicochemical properties of starches: starches were acid‐treated,5 oxidized,6–8 etherified,9 and grafted by chemical methods 10. The blending of starch with PVA11 or poly(methacrylic acid)12 has been also investigated for the property modification of natural starches.…”