Towards compatibility enhancement of biodegradable plasticized cellulose acetate and polyhydroxyalkanoate blends: Effect of calcium carbonate and maleated hybrid blend on material performance

Although blending with tougher biopolymers is a common approach to mitigate this drawback, the resulting improvement in toughness is often limited due to poor compatibility between the blend constituents. In this work, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), known as amorphous polyhydroxyalkanoate (aPHA), was incorporated into the pCA matrix at three different ratios.

Although solubility parameter calculations indicated partial miscibility between the two polymers, glass transition temperature (Tg) and morphological observations confirmed complete immiscibility. To enhance interfacial compatibility, various amounts of a compatibilizer; maleic anhydride (MA)-grafted hybrid blend, and CaCO₃ were introduced into the optimized blend ratio. Morphological analysis revealed a droplet-matrix structure in which the droplet size of the dispersed aPHA decreased upon the addition of each additive individually, demonstrating their compatibilizing effect.