2008 Volume 81 Issue 1 Pages 23-28
Poly[(R)-3-hydroxybutyrate] (P(3HB)) and its copolymers, produced by various microorganisms as an intracellular carbon and energy reserve, are biodegradable thermoplastic materials. These polymers are thus expected as a new material for a solution to problems concerning global environment. For the biodegradable polymer materials, the crystalline regions in the material play an important role in the regulation of both the degradability and the physical properties. Toward developing the high-performance biodegradable materials with desirable physical properties, we aim to reveal the morphology of crystalline region and its transformation by external field such as stress or heat at a molecular level. Here, we discuss the real-time annealing experiments of P(3HB) and its copolymer solution-grown single crystals, followed by synchrotron radiation small-angle X-ray scattering and wide-angle X-ray diffraction. The solid state reorganization of crystal thickening is attributed to partial melting-recrystallization process via the mutual rearrangement of molecular chains, which are released from the crystal lattice, between the adjacent crystals.
