Biocompatible polymer blends: Effects of physical processing on the molecular interaction of poly(vinyl alcohol) and poly(vinyl pyrrolidone)

Blending is a very effective method for manufacturing new polymeric materials; however, the process used to combine two polymers can influence the physicochemical properties of the final product. As such, the aim of this study was to investigate how the rapid removal of a solvent from a composite by the spray drying of partially hydrolyzed poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) altered the solid-state properties of the material compared to casting the blend within a film. Although thermal analysis showed that PVP acted as a plasticizer, reducing the melting point of PVA, spray drying the product rather than using a film-casting procedure improved its solid-state stability (increasing the glass transition) and resulted in the formation of a second crystalline phase within the material. Spectroscopic studies suggested that the manufacturing-induced variance in the solid-state properties of the PVA/PVP blends originated from structural differences in the composite caused by the processing method employed to form the blend. Although blending should still be considered a viable method of generating novel polymeric material, this study illustrated that through careful manipulation of the actual manufacturing process, the solid-state properties of the product can be altered. This could open a whole range of novel applications for traditionally used polymer composites.