Synthesis and Characterization of Biodegradable Polyhydroxy Butyrate-Based Polyurethane Foams

Abstract

A series of polyhydroxy butyrate (PHB)-based polyurethane (PU) foams were synthesized by reacting a mixture of PHB and polycaprolactone triol (PCLt) with an aliphatic diisocyanate, in the presence of water as blowing agent. The effects of PHB content on the polymerization kinetics and thermal properties of the foams were investigated. It is found that the polymerization rate of the foams decreases in the presence of PHB due to high viscosity of the melts induced by this material. The presence of PHB also increases the glass transition temperatures of the foams as well as the hard segments of the backbone chains. These changes can be mediated by controlling the concentration of the catalyst as well as the amount of polyethylene glycol (PEG) added. In addition, exposure of PHB-based PU foams to an enzyme medium showed a progressive degradation of PHB during the experiment. The thermal analysis was employed to quickly and accurately measure the removal of PHB from the polymer matrix.