Abstract
The thermal effects on crystallization kinetics and the band morphology of absorbable poly(p-dioxanone) (PDS) were studied in detail with TGA, AFM, DSC and polarized optical microscopy techniques. The polymer film was crystallized with isothermal and non-isothermal conditions over a wide temperature range, cooling from the melt at 140 degrees C (beyond the equilibrium melting temperature but below the degradation temperature). With the isothermal crystallization process, a well-defined spherulitic morphology of the PDS polymer, linearly growing in all directions with time, was observed. A microstructure analysis by polarized optical microscopy and AFM revealed that the crystallized PDS shows large spherulites with band morphology, the nucleation density decreases and the spacing between the band increases with crystallization temperature. The periodic band morphology of the spherulites is related to edge-on and flat-on lamella orientation. The crystallization temperature dependent spherulite growth rate displayed a bell-shaped curve, showing a highest spherulite growth rate at 60 degrees C, explained by classical nucleation theory. These results allowed a good understanding of the thermal and morphological properties of the PDS polymer over a wide temperatures range in both isothermal and non-isothermal conditions. Additionally, the crystallization and melting behaviors of the PDS polymer were studied and compared for the future application of blending with other compatible polymers, e.g. poly(epsilon-caprolactone). (c) 2020 Society of Industrial Chemistry