Miscibility of poly(Hydroxybutyrate)/poly(vinyl alcohol) melt blends plasticized with glycerol

Abstract

Poly(hydroxybutyrate)/poly(vinyl alcohol) (PHB/PVA) blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA. The PHB/PVA-glycerol compositions were 90:10, 75:25 and 50:50 w/w, being the concentration of glycerol in the PVA mixture of 10 wt %. The blends were characterized by infrared spectroscopy, dynamic-mechanical thermal analysis, and scanning electron microscope of the fragile fractured surface. The results showed one single phase blend, indicating miscibility corroborated by the presence of a single glass transition temperature. The blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.