Chemical modification of chitosan under high-intensity ultrasound.
Chitosan (CTS), a biocompatible, biodegradable, non-toxic polymer, dissolves in water only if pH is lowered under 6.5, when a substantial fraction of the amino groups is protonated. Its range of application has been much extended by partially depolymerising it or converting it to water-soluble derivatives. Working under high-intensity ultrasound at 17.8-18.5 kHz, using either a simple horn or a cup horn, we achieved a controlled depolymerization of CTS, also prepared in high yields several derivatives that can be useful intermediates for further chemical modification, as well as several water-soluble derivatives that lend themselves to a host of industrial applications. Compared to conventional methods, all these reactions went to completion in considerably shorter times at lower temperatures.
Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, Via Giuria 9, 10125 Torino, Italy. giancarlo.cravotto@unito.it
Giancarlo
G
Cravotto
Silvia
S
Tagliapietra
Bruna
B
Robaldo
Michele
M
Trotta
D048271:Chitosan / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D008745:Methylation; D010084:Oxidation-Reduction; D011829:Radiation Dosage; D012995:Solubility; D013010:Sonication; D014783:Viscosity; D014867:Water / Q000737:chemistry*
D014867:Water; D048271:Chitosan