Hydrophilic polyurethane networks based on poly(ethylene oxide): Synthesis, characterization, and properties. Potential applications as biomaterials

Hydrophilic polyurethane networks have been synthesized by step growth polymerization between polyethylene oxide) precursor polymers and suitable aliphatic or aromatic pluriisocyanates. The reactions have been carried out in organic solvents such as dioxane. The quantitative exchange between dioxane and water yields optically transparent hydrogels of high hydrophilicity exhibiting improved mechanical properties. The final structure of the networks and their ultimate properties depend upon several parameters such as the type of the pluriisocyanate used, the number-average molecular weight, and the concentration of the precursor polyethylene oxide) as well as its polydispersity. The solvent, the temperature, and the catalysts influence considerably the rate and the total duration of the process. The networks obtained are characterized by their equilibrium swelling degrees in dioxane and in water and by their elastic moduli arising from uniaxial compression measurements. In most cases, the materials obtained are optically perfectly transparent, highly hydrophilic with satisfactory mechanical properties, and therefore suitable as potential biomaterials.