Transport water and molecular mobility in novel barrier membranes with different morphology features

Bacterial poly(3-hydroxybutyrate) (PHB) - a new biopolymer and its derivati ves are being extensively applied in medicine, biotechnology and membrane t echnologies. The relationship between structure-transport parameters and mo lecular mobility of PHB was investigated by quartz McBain's microbalance, X -ray diffraction and ESR method. Two types of the PHB membranes with differ ent structural organisation-isotropic and textured-were studied. The specif ic features of the sorption and diffusion characteristics of PHB are relate d to the structural organisation. The polymer matrixes are characterised by significantly microstructural heterogeneity as it was shown by the spin pr obe (TEMPO/TEMPOL) measurements. A non-crystalline phase of PHB includes tw o kinds of microfields with different molecular mobility. Moisture is found to change both the velocity of molecular motion and the mole content of su ch microfields. The diffusion behaviour of the membranes has been explained in accordance with dynamic information based on the ESR method.