Melt behaviour, crystallinity and morphology of poly(p-dioxanone)

The melt behaviour of poly(p-dioxanone) (PPD) has been studied by differential scanning calorimetry (DSC). Crystallinity and morphology were evaluated by modulated differential scanning calorimetry (MDSC) and polarizing optical microscopy. The melting curves showed two melting endotherms, a higher melting (HM) peak at a constant temperature of 105°C and a lower melting (LM) peak at temperatures depending on the crystallization temperature Tc. The corresponding peak temperature increased linearly with Tc, yielding an extrapolated value for the equilibrium melting temperature, Tm°, of 114°C. The occurrence of HM peak is a result of recrystallization. The optical micrographs showed a spherulitic morphology, with regular concentric rings, which might be caused by a periodical twisting of the lamellae during crystallization.