Viscoelastic properties of polyvinyl alcohol-borax wound dressing hydrogels

In the present work, viscoelastic properties of polyvinyl alcohol (PVA) hydrogel physically crosslinked using disodium tetraborate (Borax) have been studied. Due to its low toxicity and good viscoelastic properties, the PVA-Borax (PB) hydrogels can be used as wound dressing materials. Interactions between PVA chains and Borax molecules were studied by means of FTIR spectroscopy, while viscoelastic properties of prepared PB hydrogel were measured in the oscillatory shear mode. It was observed that with increasing the Borax: PVA ratio the low frequencies storage modulus shows an increasing-decreasing trend. The highest viscoelastic properties were achieved in a hydrogel sample prepared by borax: PVA ratio of 1/4. At low Borax concentrations, crosslinking density and physical interactions are too low leading to formation of highly fluidic hydrogel without enough viscoelastic properties. Meanwhile, at high Borax concentrations (2-4 wt.%), mainly due to increasing in trigonal borax complexes, the crosslinking density was decreased resulted in sharp reduction of storage modulus