Characterization of the microstructure of poly hydroxybutyrate (PHB) copolymer during their post-fabrication annealing at room temperature

The mechanical properties of bio-based, biodegradable PHB copolymers are known to change considerably over a period of time after parts are fabricated. This study focused on the changes in semi-crystalline morphology during this aging process. The semi-crystalline morphology was characterized using the three-phase model (crystalline, mobile amorphous and rigid amorphous phases). Thermal analysis (DSC and DMTA) were combined with x-ray diffraction and refractive indices measurements to provide a comprehensive picture of the microstructural changes.