Polymer and Materials
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
An experimental study is reported of the dependence of the melting temperature Tm on the crystallization temperature Tc for molecular weight fractions of poly(hexamethylene oxide) in the range from Mn=2260 to Mn=35 500, with attention to the level of crystallinity.It has been found that for the highest molecular weight fraction, at low levels of crystallinity, the extrapolated linear relation Tm vs. Tc yields an equilibrium melting temperature of 346,5K in very good accord with theoretical expectations. Moreover, the behaviour and theory for low-molecular-weight fractions is analyzed.The enthalpy of fusion for poly(hexamethylene oxide) has been determined from two kinds of experiments: by measuring calorimetrically the apparent heat of fusion at different levels of crystallinity, and by using the polymer-diluent method in decahydronaphthalene and 1,2,3,4-tetrahydronaphthalene. The enthalpy of fusion was found to be 54-57 cal/g (=226-238J/g).
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