Crystallization Kinetics and Melting Behaviour of the Novel Biodegradable Polyesters Poly(propylene azelate) and Poly(propylene sebacate)

Novel biodegradable poly(propylene sebacate) (PPSeb) and poly(propylene azelate) (PPAz) polyesters were synthesized and fully characterized using WAXD, standard DSC, high-rate DSC, and modulated-temperature DSC. Multiple-melting behaviour, observed for samples isothermally crystallized from the melt, was attributed to sequential melting-recrystallization-remelting. Study of isothermal and nonisothermal crystallization kinetics revealed a higher crystallization rate for PPSeb compared to PPAz. The Avrami and the Lauritzen-Hoffman models were successfully applied to DSC measurements, using also data obtained after self-nucleation, in order to diminish the effect of primary nucleation. Finally, the effective activation energy was estimated using the differential isoconversional method of Friedman.