Investigation of the viscoelastic behavior of PVA-P(AAm/AMPS) IPN hydrogel with enhanced mechanical strength and excellent recoverability

The current work emphasizes on the creep and creep-recovery measurements to analyze the viscoelastic behavior of the synthesized PVA-P(AAm/AMPS) IPN hydrogel. The structure and surface morphology of the P(AAm/AMPS) IPN hydrogel were characterized by Fourier Transform Infrared Transform Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and X-ray diffraction (XRD). The effect of temperature (25, 30, 35 and 40 ˚C) on the microstructure and rheological properties of the IPN hydrogel was studied. Initially, the effect of shear stress, creep and creep-recovery duration was investigated on the viscoelastic properties of the IPN hydrogel. Then the burger model was fitted on the creep-recovery data. A linear increase in deformation was observed with increasing the creep duration. A recovery duration of nearly 11 min seemed to be sufficient to obtain maximum recovery. Maximum creep compliance decreased from 0.140441 Pa −1 to 0.0144405 Pa −1 by rising temperature from 25 to 40 ˚C respectively. Maximum creep recovery of IPN hydrogel was observed at higher temperature i.e., 40 ˚C. Thixotropic behavior of IPN hydrogel was observed by different ways such as 3 interval thixotropic (3ITT) and hysteresis loop tests. Thixotropic analysis reveals the partial recoverability of the IPN hydrogel, but its recovery percentage increased with the rise in temperature. Amplitude sweep test reveals the stability of synthesized IPN hydrogel. Finally, the rheological properties of synthesized IPN hydrogel were better at higher temperature. Overall, the percent recoverability and enhanced mechanical behavior make PVA-P(AAm/AMPS) IPN hydrogel best fit for multiple applications.