Structural features of LDPE-poly(3-hydroxybutyrate) blends

The structure and morphology of biodegradable extruded polymeric films base d on LDPE and poly(3-hydroxybutyrate) (PHB) were studied by a combination o f methods including polarization IR spectroscopy, DSC, and scanning electro n microscopy (SEM). The components of LDPE-PHB blends containing 0-32% PHB are immiscible and form morphological structures (phases) with well disting uishable phase boundaries between dispersed phase and dispersion matrix. Th e process of film formation by extrusion is accompanied by sharp decrease i n the degree of crystallinity in both LDPE and PHB components. Measurements of the dichroism for the characteristic crystallinity bands of both compon ents in the IR spectra of blends showed that the axes of macromolecules in the grains are predominantly mutually parallel and the mains are oriented s o that the axes of mutual orientation are perpendicular to the direction of extrusion. The geometry of ribbon-like and cylindrical structural elements of PHB reinforcing the LDPE matrix in the blend was studied.