Abstract
This study demonstrates that the step-heating calorimetry, which is a kind of temperature-modulated differential scanning calorimetry, can provide valuable information on the polymer melting. Time-dependent heat flow due to the melting of lamellar crystallites in a narrow range of thickness can be directly observed, from which thickness distribution of lamellar crystallites and thickness dependence of the melting kinetics are deduced. A sample of poly(e-caprolactone) was used as a model material of semi-crystalline polymer, which has high crystallinity (0.79) so that no recrystallization and/or reorganization occur during melting in the step-heating scan. It was revealed that superheating dependence of the melting rate coefficient increases with increasing lamellar thickness, which may be attributed to variation of the fold surface roughness with respect to lamellar thickness. Analysis based on the cylindrical nucleation model revealed much lower free energy values of lateral surface than that evaluated from crystallization behavior, suggesting that the nucleus for melting is more stable than that for crystallization.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
