Polymer, Vol.36, No.4, 815-819, 1995
Rheological Study of the Gelation Kinetics of the Scleroglucan-Zirconium System
The formation kinetics of scleroglucan-zirconium gels was studied using theological measurements. It was possible to determine such kinetics by following the change in solution elastic modulus as a function of time. Gelation kinetics was found to increase vs. polymer concentration according to a power law function. In contrast, when zirconium concentration was increased, gelation kinetics was found to increase, reaching a critical value and then decreasing drastically. On the other hand, the influence of temperature showed that the crosslinkage process was endothermic (W-A approximate to 33 kJ mol(-1)). The last parameter studied was the pH. Our results clearly demonstrate that gelation was enhanced by pH elevation. So, despite the complicated zirconium chemistry, an explanation of observed behaviour was attempted on the basis of the presumed formed species.