| This dissertation constitutes the studies about the biomedical materials research of novel polyurethanes. These elastic and degradable polyurethanes exhibited the potential for drug delivery, scaffold fabrication by novel ink-jet printing technology or other biomedical applications. This dissertation includes two parts about two different types of polyurethanes.;In the first part of this dissertation, we studied a polyurethane that was synthesized from methylene di-p-phenyl-diisocyanate (MDI), polycaprolactone diol (PCL-diol) and N, N-bis (2-hydorxyethyl)-2-aminoethane-sulfonic acid (BES). MDI, PCL-diol and BES were polymerized into polyurethane and served as the hard segment, soft segment and chain extender respectively. The effects of the chain extender BES on the degradation, mechanical properties, hydrophilicity, and cytophilicity of polyurethane were evaluated by comparison with the polyurethane that was chain extended by 2,2'-(methylimino)diethanol (MIDE).;In the second part of this dissertation, we studied a polyurethane synthesized from hexamethylene diisocyanate (HDI), polycaprolactone diol (PCL-diol), and a bicine chain extender. The chemical structure, mechanical properties, degradation rate, and swelling ratio were characterized by comparing the polymer with a polyurethane containing a 2,2'-(methylimino)diethanol (MIDE) chain extender. Due to the incorporation of negatively charged carboxyl side groups, the bicine extended polyurethane exhibited the environmental stimuli sensitivity, the polyurethane's physical properties change in response to environmental stimuli, such as pH, ionic strength and temperature. |
