Reversible melting of high molar mass poly(oxyethylene)

摘要: Abstract The heat capacity, C p , of poly(oxyethylene), POE, with a molar mass 900,000 Da, was analyzed by temperature-modulated differential scanning calorimetry, TMDSC. high POE crystals are in folded-chain macroconformation and show some locally reversible melting, starting already at about 250 K. At 335 K the thermodynamic capacity reaches level melt. end melting high-crystallinity sample quasi-isothermally varying modulation amplitudes from 0.2 to 3.0 K study crystallinity. A new internal calibration method developed which allows quantitatively assess small fractions reversibly presence large amounts irreversible melting. specific reversibility decreases values vicinity but does not seem go zero. is close symmetric fraction crystallizing slower than i.e., under chosen condition crystallization remains reversing. collected data behave as one expects for governed molecular nucleation would expect formation an intermediate mesophase on crystallization. active surface flexible macromolecules.