Ultrasonic degradation of aqueous carboxymethylcellulose: effect of viscosity, molecular mass, and concentration.
It is well established that prolonged exposure of solutions of macromolecules to high-energy ultrasonic waves produces a permanent reduction in viscosity. It is generally agreed as well and also this study proved the hydrodynamic forces to have the primary importance in degradation. According to this study the sonolytic degradation of aqueous carboxymethylcellulose polymer or polymer mixtures is mainly depended on the initial dynamic viscosity of the polymer solution when the dynamic viscosity values are in the area range enabling intense cavitation. The higher was the initial dynamic viscosity the faster was the degradation. When the initial dynamic viscosities of the polymer solutions were similar the sonolytic degradation was dependent on the molecular mass and on the concentration of the polymer. The polymers with high molecular mass or high polymer concentration degraded faster than the polymers having low molecular mass or low polymer concentration. The initial dynamic viscosities were adjusted using polyethyleneglycol.
Antti
Grönroos
G
VTT, P.O. Box 1603, FIN-40101 Jyväskylä, Finland. Electronic address: antti.gronroos@vtt.fi.
Pentti
Pirkonen
P
VTT, P.O. Box 1603, FIN-40101 Jyväskylä, Finland.
Hanna
Kyllönen
K
VTT, P.O. Box 1603, FIN-40101 Jyväskylä, Finland.
D002266:Carboxymethylcellulose Sodium / Q000528:radiation effects*; D007202:Indicators and Reagents; D008970:Molecular Weight; D012996:Solutions; D014465:Ultrasonics; D014783:Viscosity; D014867:Water
D007202:Indicators and Reagents; D012996:Solutions; D014867:Water; D002266:Carboxymethylcellulose Sodium