Lamellar crystallization of poly(trimethylene terephthalate)

The dependence of lamellar thickness on the melting temperature and crystallization temperature and the crystallization temperature dependence of the growth rate for poly(trimethylene terephthalate) (PTT) were examined with small-angle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and optical microscopy. The melting temperature of the isothermally crystallized PTT lamellar stack structure was determined by X-ray measurements. The equilibrium melting temperature of PTT was determined to be 290.5 degrees C from the relationship between the melting temperature and the lamellar thickness. The relationships of supercooling to the lamellar thickness and the growth rate were analyzed. The excess thickness delta l = 7.1 angstrom was obtained from the data provided above for the crystallization temperature, T-c = 173.7 degrees C. The temperature dependence of the lamellar thickness below T-c = 173.7 degrees C suggested crystallization through a mesophase. The temperature dependence of the growth rate was explained by secondary nucleation theory over a wide crystallization temperature range.

Automated summary

The relationship between lamellar thickness and melting temperature and crystallization temperature, as well as the growth rate and crystallization temperature of poly(trimethylene terephthalate) (PTT) were investigated using small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and optical microscopy. The X-ray measurements determined the melting temperature of the isothermally crystallized PTT lamellar stack structure. The equilibrium melting temperature of PTT was found to be 290.5 degrees C based on the relationship between melting temperature and lamellar thickness. The study analyzed the relationships of supercooling with lamellar thickness and growth rate. The data provided a value of 7.1 angstrom for the excess thickness (delta l) at a crystallization temperature (T-c) of 173.7 degrees C. The temperature dependence of lamellar thickness below T-c = 173.7 degrees C indicated crystallization through a mesophase. The temperature dependence of the growth rate was explained by the secondary nucleation theory across a wide range of crystallization temperatures.