Crystallization and Melting Behaviors of PPC‐BS/PVA Blends

The isothermal crystallization and melting behaviors of poly(propylene carbonate) end‐capped with benzenesulfonyl/poly(vinyl alcohol) (PPC‐BS/PVA) blends over rich PVA composition range were first investigated by differential scanning calorimetry (DSC). PPC‐BS/PVA interaction parameter, χ12, calculated from equilibrium melting temperature depression was −0.44, revealing miscibility of PPC‐BS with PVA in the melt and favorable interactions. The temperature dependence of crystallization rate constant at initial crystallization stage was analyzed using the modified Lauritzen‐Hoffman expression. The chain width, a0, the thickness of a monomolecular layer, b0, the fold and lateral surface free energies, σe and σ, and the work of chain folding, q, for neat PVA were first reckoned to be 4.50 Å, 4.78 Å, 76.0 erg · cm−2, 8.81 erg · cm−2, and 4.70 kcal · mol−1, respectively. The values of σe and q for PVA in PPC‐BS/PVA blends exhibited a maximum in the neighborhood of 10/90 PPC‐BS/PVA, respectively. Kinetic analysis of the temperature dependence of crystallization rate constant at initial crystallization stage for neat PVA and PPC‐BS/PVA blends. magnified image Kinetic analysis of the temperature dependence of crystallization rate constant at initial crystallization stage for neat PVA and PPC‐BS/PVA blends.