Modification of polymers by ultrasound treatment in aqueous solution

Abstract

AbstractUltrasound treatment, as an alternative to chemical and radiation-based processes, is an interesting technique for the modification of average molecular weights of natural and synthetic polymers in aqueous solution. Degradation is the observed main effect for strongly hydrophilic compounds - poly(acrylic acid) and chitosan. It is demonstrated that this process is caused by OH radicals as well as mechanochemical effects. Studies on more hydrophobic polymers - poly(ethylene oxide) and poly(ethylene glycol)s - indicate that here cross-linking and degradation occur side-by-side. The net effect of these competing reactions depends on the length of the polymer chains.