Compression testing and measurement of material properties of a double network hydrogel

Abstract

Double network hydrogel samples were synthesized and manufactured out of polyacrylamide (PAAm) and alginate solutions. They were casted into cube molds with each side measuring 20 mm. Samples were tested under compressive loads in cyclic compression tests and stress relaxation tests. A viscoelastic model was applied and material properties were calculated using the experimental data. The elastic modulus of these PAAm-alginate gels was found to be 35kPa, while the viscosity, [eta], was found to be 1.43 kPa-s. The viscous response was found to have a dependency on the strain rate by an exponential factor of 0.26. Using the applied theoretical model and the experimentally determined material properties, you can then characterize the mechanical response of the PAAm-alginate hydrogel when it undergoes small strains.