Poly(3-hydroxybutyrate) and poly(3-hydroxyoctanoate) blends: Morphology and mechanical behavior

Blends of bacterial poly(hydroxybutyrate) (PHB) with poly(hydroxyoctanoate) (PHO) were prepared by co-dissolving the two polyesters in chloroform and casting the mixture. To probe the question of blend miscibility, scanning electron microscopy (SEM) observations and differential scanning calorimetry (DSC) spectra were collected for the blends and blend components as well. It has been observed that PHB shows no miscibility at all with PHO, resulting in two-phase systems in which the nature of the continuous phase is composition-dependent. Dynamic mechanical analysis and tensile properties of these materials were also investigated. The morphology of the blend strongly influences the mechanical behavior. The mechanical properties of these materials have been predicted from a model involving the percolation concept. It takes both linear and nonlinear mechanical behaviors into account and allows for the effect of the lack of adhesion between material domains and/or breakage of one of the component.