Resumo

VITTORIA, Balsamo  e  M. GOUVEIA, Laura. Estimation of thermodynamic and kinetic secondary nucleation parameters in poly(styrene-co-maleic anhydride)/poly(e- caprolactone) blends. Rev. LatinAm. Metal. Mater. [online]. 2011, vol.31, n.1, pp.26-34. ISSN 0255-6952.

The estimated equilibrium melting points of the poly(e-caprolactone) (PCL) fraction in poly(styrene-co-maleic anhydride)/poly(e-caprolactone) blends (PSMA14/PCL), where the PSMA has 14 mol% of maleic anhydride units, were successfully analyzed by means of the Nishi-Wang equation yielding a negative Flory-Huggins interaction parameter ( c = _-1.46 ). This result indicates strong interactions between the blend components, whose magnitude do not change with composition. The kinetics of the PCL spherulitic growth was investigated as a function of composition and crystallization temperature by polarized optical microscopy and analyzed using the traditional Lauritzen-Hoffman (LH) secondary nucleation theory, as well as a modified version of it. The composition dependence of nucleation constants, K_g, in crystal growth regime II suggests that crystal fold energy, se, decreases with the addition of PSMA14, but when the concentration of PSMA14 reaches 20% or more, non additional effect is observed, a fact that was attributed to the PCL effective concentration considered in the Lodge and McLeisch model for miscible blends

Palavras-chave : Miscible Blends; Crystallization; Poli( e-caprolactone).