Synthesis and characterization of biodegradable segmented poly(ester urethanes) derived from poly(caprolactone diols) and poly(L-lactide diols)

Segmented poly(ester urethanes) containing biodegradable hard and soft segments were synthesized from poly(caprolactone diols) with M-n = 540-3470, 1,6-hexamethylene diisocyanate, and poly(lactide diols) with M-n = 240-3200 as chain extenders. Using DSC and NMR and IR spectroscopy, the effects of the molecular mass of hard and soft segments on the structure, thermal behavior, and mechanical properties of the synthesized polymers, as well as the biodegradability of films initiated by Rhizopus arrhizus lipase in a buffer solution (pH 7.4) at 37 degreesC, were studied. The data of DSC and IR spectroscopy together with the calculated values of the molecular packing coefficient K indicate that soft segments derived from poly(caprolactone diols) exhibit a higher level of ordering compared to hard segments: The weight loss from the surface of films due to enzymatic degradation decreases with increasing the degree of crystallinity of soft and hard segments.