Miscibility in Crystalline/Amorphous Blends of Poly(3-hydroxybutyrate)/ DGEBA

Abstract

A differential scanning calorimetry (DSC) and smallangle X-ray scattering (SAXS) study of miscibility in blends of the semicrystalline polyester poly(3-hydroxybutyrate) (PHB) and amorphous monomer epoxy DGEBA (diglycidyl ether of bisphenol A) was performed. Evidence of the miscibility of PHB/DGEBA in the molten state was found from a DSC study of the dependence of glass transition temperature (Tg) as a function of the blend composition and isothermal crystallization, analyzing the melting point (Tm) as a function of blend composition. A negative value of Flory–Huggins interaction parameter vPD was obtained. Furthermore, the lamellar crystallinity in the blend was studied by SAXS as a function of the PHB content. Evidence of the segregation of the amorphous material out of the lamellar structure was obtained.