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I. Neamtu, L. E. Nita, M. Bercea, A. P. Chiriac

The rheological behavior of chemically crosslinked hydrogels based

on poly(acrylamide) (in English)

Polimery 2009, No 11/12, 795


DOI: dx.doi.org/10.14314/polimery.2009.795

Summary

The effects of different ratios of monomer/crosslinking agent and initiator/activator (potassium peroxydisulfate/ascorbic acid) concentrations on the polymerization of acrylamide (AAm) crosslinked with N,N-methylene-bis-acrylamide (Bis) were studied by dynamic oscilatory testing and gel point (GP) quantitative determination. In the studied conditions, rheological response of PAAm gelation - elastic and viscous moduli, loss tangent and complex dynamic viscosity - indicates these properties could transit between elasticity and viscoelasticity dependently on the reaction time and reactants' ratios. After a certain induction period during which the elastic modulus is close to zero, it increases monotonically until equilibrium is reached.


Key words: hydrogel, poly(acrylamide), redox initiation, viscoelastic properties, gel point, dynamic oscillatory method, in situ testing


I. Neamtu, L. E. Nita, M. Bercea, A. P. Chiriac

The rheological behavior of chemically crosslinked hydrogels based on poly(acrylamide) (in English)