Degradation of chitosan and starch by 360-kHz ultrasound

文档简介reductionofmolecularweightofbothpolysaccharides.IthasbeendemonstratedthatattheappliedultrasoundfrequencydegradationiscausedbothbyOHradicalsandmechanochemicaleffects.InAr-saturated2!10K2moldmK3chitosansolutions,pH3,atanultrasounddoserateof170WkgK1,theaveragesonochemicalchainscissionyieldinthesonicationtimerangeof090minisca.8!10K11molJK1.Thisyieldhasbeenshowntodependonpolymerconcentration,ultrasoundpowerandgasusedtosaturatethesolution.Scissionisaccompaniedbysidereactionsleadingtotheformationofcarbonylgroups.Ultrasound-inducedchainscissionofstarchproceedswithloweryield,oneofthereasonsbeingprobablythedifferentchainconformationwhencomparedwithrod-likechitosanmacromolecules.q2004ElsevierLtd.Allrightsreserved.