Original Articles
Kannissery Pramod*, Salim Shan
Abstract
Rheology refers to the study of flow and deformation of materials. Rotational and oscillation experiments are most important methods for rheological profiling of polymers. The objective of the present study was to unveil the rheological profile of Carbopol 940 hydrogel, at a concentration of 1%w/w, by subjecting to flow, frequency sweep, creep recovery and thixotropy measurements. From the flow curve measurements it was observed that shear rate has influence on viscosity and shear stress. Carbopol hydrogel behaved as a viscoplastic or yield stress fluid. Higher values for loss modulus than storage modulus from frequency sweep experiments indicated that elastic component is less is prevailing in the hydrogel than the elastic component. Complex viscosity was found to decrease on increasing frequency and thus a pseudoplastic behaviour of hydrogel was confirmed. From the creep recovery plot it was inferred that the hydrogel sample behaves as viscous material at the applied stress. The hydrogel behaved as an ideal viscous material. High structure recovery ratio and hysteresis area obtained demonstrated a good thixotropic property for the hydrogel. Future studies with varying test parameters and conditions would be useful in further elucidating the mechanistic properties of Carbopol hydrogel under stress