Single- and double-ring spherulites in poly(nonamethylene terephthalate)

A new mechanism of formation of ring-banded spherulites was discovered, where three different types of spherulites were present in poly(nonamethylene terephthalate) (PNT) cast in thin film forms. The growth and morphological features in three ring-banded spherulites were compared and analyzed using polarized/non-polarized light microscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) and element analysis by energy dispersive spectroscopy (EDS) on surfaces of spherulites. Three types of spherulites (labeled: Type-0, 1, and 2) are possible in PNT when crystallized at wide range of crystallization temperature (Tc); however, only two of the three types can co-exist in PNT at a given Tc. At lower Tc (