The effect of processing on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers

Semi-crystalline poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers ar e biodegradable systems with potential as substrates for use in tissue rege neration. Previous studies have shown that severe embrittlement occurs on s torage at room temperature restricting their application possibilities. Con cepts such as secondary, advancing crystallisation causing changes in the a morphous/crystalline ratio have been mooted as the cause of the embrittleme nt. Using films prepared by extrusion and compression moulding procedures w e have attempted to probe not only the pure amorphous and crystalline phase s but also the interfacial region. Interpretation of dynamic mechanical and dielectric data highlights the changes in the nature of the interfacial re gion on processing. Moreover, the use of the Thermally Stimulated Discharge technique is a powerful probe for highlighting the morphological changes i nduced in multiphase systems by the processing step. (C) 2001 Kluwer Academ ic Publishers.