Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10603153 | Carbohydrate Polymers | 2005 | 10 Pages |
Abstract
Effects of 360-kHz ultrasound on aqueous solutions of chitosan and starch were studied. This treatment is an efficient procedure for reduction of molecular weight of both polysaccharides. It has been demonstrated that at the applied ultrasound frequency degradation is caused both by OH radicals and mechanochemical effects. In Ar-saturated 2Ã10â2 mol dmâ3 chitosan solutions, pH 3, at an ultrasound dose rate of 170 W kgâ1, the average sonochemical chain scission yield in the sonication time range of 0-90 min is ca. 8Ã10â11 mol Jâ1. This yield has been shown to depend on polymer concentration, ultrasound power and gas used to saturate the solution. Scission is accompanied by side reactions leading to the formation of carbonyl groups. Ultrasound-induced chain scission of starch proceeds with lower yield, one of the reasons being probably the different chain conformation when compared with rod-like chitosan macromolecules.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Renata Czechowska-Biskup, Bozena Rokita, Salah Lotfy, Piotr Ulanski, Janusz M. Rosiak,