Thermodynamic properties and crystallization behavior of poly(p-phenylene succinate)

The equilibrium thermodynamic properties and crystallization behavior of po ly(p-phenylene succinate) (PPSc) were examined using differential scanning calorimetry (DSC) and a wide-angle X-ray diffractometer. When PPSc quenched into liquid nitrogen, the PPSc still showed 60 J/g of the heat of fusion, indicating that PPSc crystallizes too fast to be quenched to a glassy state . The equilibrium heat of fusion (Delta H degrees) of PPSc and its equilibr ium entropy of fusion (Delta S degrees) were estimated to be 28 and 48 J/mo l K, respectively. The effect of the molecular weight and undercooling on P PSc crystallization was analyzed by the Avrami expression. The crystallizat ion rate of PPSc was highest at about 276 degrees C, regardless of molecula r weight when the sample was isothermally crystallized. This temperature wa s higher than that of poly(ethylene terephthalate) (PET) by 100 degrees C. The crystallization rate was highest when the number average molecular weig ht of PPSc was about 20,000 g/mol. (C) 1999 John Wiley & Sons, Inc.