GELATION CONTROL OF THE SCLEROGLUCAN ZIRCONIUM SYSTEM USING OXYACIDS

In numerous applications of gels, one sometimes needs to control the g elation process. Here we focus our investigations on a particular mean s to attain this aim for the scleroglucan-zirconium system. For this p urpose some oxyacids have been added to the system. Since the oxyacids involved are known to form complexes of various stability with zircon ium, the whole gelation system follows from competition between oxyaci d-zirconium and polymer-zirconium complex formation. The zirconium use d in this study was in the form of zirconium lactate, and our results show that gelation diminishes in the order of citric, malic, tartaric and lactic acids. This hierarchy was compared to that expected from av ailable equilibrium constants of oxyacid-zirconium complexes.