Light scattering studies on ternary polymer blend solutions comprising poly(hydroxybutyrate)

Abstract

We report on light scattering studies of polymer blend solutions in trifluoroethanol (TFE). The polymer blends comprised poly(3-hydroxybutyrate) (PHB) in combination with poly(ethylene oxide) (PEO) and poly(epsilon-capro-lactone) (PCL). PHBs of two different molecular masses were used. Relevant quantities were obtained from Zimm plots. All quantities display non-linear dependencies on blend composition. For the blend system with PEO and PHB of lower molecular mass, we observed a negative excess of the second virial coefficient, which is indicative of the miscibility of the constituents. The opposite is observed for blends with PCL. The situation changes in blends with PEO and PHB of sufficiently high molecular mass. It turns out that PEO is only miscible with PHB of high molecular mass if it is the major component. This can be concluded from both light scattering and viscosity results.