Isothermal and nonisothermal melt-crystallization kinetics of syndiotactic polystyrene

Analyses of the isothermal and nonisothermal melt kinetics for syndiotactic polystyrene have been performed with differential scanning calorimetry, and several kinetic analyses have been used to describe the crystallization process. The regime II-->III transition, at a crystallization temperature of 239degrees, is found. The values of the nucleation parameter K-g for regimes II and III are estimated. The lateral-surface free energy, sigma = 3.24 erg cm(-2), the fold-surface free energy, sigma(e) = 52.3 +/- 4.2 erg cm(-2), and the average work of chain folding, q = 4.49 +/- 0.38 kcal/mol, are determined with the (040) plane assumed to be the growth plane. The observed crystallization characteristics of syndiotactic polystyrene are compared with those of isotactic polystyrene. The activation energies of isothermal and nonisothermal melt crystallization are determined to be DeltaE = -830.7 kJ/mol and DeltaE = -315.9 kJ/mol, respectively.