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K. Pielichowski, K. Flejtuch

RAPID COMMUNICATION: Modulated temperature DSC studies on the phase transitions

of poly(ethylene oxide). Effect of temperature step

Polimery 2003, No 6, 455


Summary

Phase behaviour of poly(ethylene oxide) (PEOX) was investigated by modulated temperature differential scanning calorimetry (DSC) - step scan alternating DSC at different temperature steps. Additional features of reversible and non-reversible components during phase transitions can be found. By increasing the temperature step between subsequent isothermal segments the reversible component of the melting process was decreasing. This effect is due to ashift of the equilibrium state of melting-recrystallization reversible processes towards higher degree of conversion that hinders molecular nucleation and recrystallization. Analysis of the non-reversible component during crystallization showed that an increase in the step caused avery distinct increase in the non-reversible component signal due to enhanced crystallization of the less-defected structures which was facilitated by larger temperature gradient.


Keywords: poly(ethylene oxide), modulated temperature differential scanning calorimetry, effect of temperature step, phase transitions, reversible and non-reversible components


K. Pielichowski, K. Flejtuch

Modulated temperature DSC studies on the phase transitions of poly(ethylene oxide). Effect of temperature step