Swelling behavior of novel polyurethane hydro-xerogels

Summary

Polyurethane hydro-xerogels derived from PEG-modified urethane acrylates (PMUA), containing hydrophilic segment (polyoxyethylene groups) and hydrophobic segment at the same molecule, were prepared and their swelling behaviors were evaluated.

Hydro-xerogels of PMUA were prepared using gelation process of PMUA emulsions. these gels could be swelled at both of water and dioxane, moreover, the swelling ratio of these gels at dioxane and water were changed with composition ratio of water to PMUA in the preparation of gel. In aqueous medium, swelling ratio of these gels increased with the increase in composition ratio of water to PMUA. However, in organic medium (Dioxane), swelling ratio decreased as the composition ratio of water increased. Additionally, as the reaction molar ratio of PEG to 2-HEMA increased, swelling ratio of gels at water increased. These results were due to microstructure of PMUA gels, which was formed by phase separation between hydrophilic and hydrophobic segments in the course of gelation.