Hydrogels based on waterborne poly(urethane-urea)s by physically cross-linking with sodium alginate and calcium chloride

Waterborne poly(urethane-urea)s (WPUUs) can be employed as a base for the preparation of new materials with novel properties and applications, such as hydrogels. In this work, sodium alginate (SA) was incorporated into WPUUs and their nanocomposites with TiO2 nanoparticles. The influence of the addition of SA and TiO2 nanoparticles on the final properties of WPUUs based hydrogels was investigated. It was proven that the hydrogen bonding interactions that took place between WPUU and SA strongly affected the final properties. The glass transition temperature and thermal stability of investigated hydrogels were affected depending on the soft segment composition. The prepared hydrogels exhibited swelling ability in an acidic medium. The porous structure of the prepared hydrogels was confirmed by the scanning electron microscope (SEM) measurements. In fact, the mechanical properties indicated an improvement in the compressive modulus with the increase of the SA content. Furthermore, the prepared hydrogels allowed the cell proliferation of human fibroblasts.