Biodegradable polyurethanes from crystalline prepolymers

Polyurethanes in the solid state are commonly used in many structural and medical applications. They are obviously obtained by the polyaddition reaction, where usually ethylene glycol is used as the chain extender. This paper deals with the fabrication of polyurethanes from crystalline prepolymers where water is used as a chain extender. Biodegradable polyurethanes were synthesized from: poly(ε-caprolactono)diol (PCL), 4,4′methylenebis(cyclohexyl) isocyanate (HMDI) and distilled water (w) as a chain extender. The prepolymer was crystallized at three different temperatures: 7, 22 and 30 °C, respectively. The materials were subjected to degradation in a solution of phosphate buffered saline (PBS) at the temperature of 37 °C, where the solution was changed every week. The results of the physical, mechanical and thermal properties, as well as sample's surface observations after the degradation are presented in the comparison to polyurethane obtained in a polyaddition reaction with ethylene glycol as a chain extender. Biodegradable polyurethanes obtained from crystalline prepolymers extended by water exhibit better mechanical properties and higher degradation rate in a solution of phosphate buffered saline (PBS) at the temperature of 37 °C than biodegradable polyurethanes obtained by the polyaddition reaction with the application of ethylene glycol as a chain extender.