Solid-state processing of PHB-powders

Poly(3-hydroxybutyrate) (PHB) is a completely biodegradable polyester, produced by bacterial fermentation. Because of poor thermal stability, melt processing of the material is accompanied by thermal degradation and poor mechanical properties. To prevent thermal degradation, a solid-state processing technology has been applied. The extrusion of PHB-powder at temperatures far below the melting point leads to products of improved mechanical properties. In particular. the ductility of the material increases considerably compared to traditional melt processed PHB. The improved mechanical properties have been attributed to structural differences on the molecular and supermolecular level.