Morphology and Mechanical Properties of LDPE-Poly(3-Hydroxybutyrate) Films

摘要

The structure and morphology of biodegradable extruded polymeric films based on LDPE and poly(3-hydroxybutyrate) (PHB) were studied by a combination of methods including polarization IR spectroscopy, DSC, and scanning electron microscopy (SEM). The components of LDPE-PHB blends containing 1-32% PHB are immiscible and form morphological structures (phases) with well distinguishable phase boundaries between dispersed phase and dispersion matrix. The process of film formation by extrusion is accompanied by sharp decrease in the degree of crystallinity in both LDPE and PHB components. Measurements of the dichroic ratio for the characteristic crystal-sensitive absorption bands of both components in the IR spectra of blends showed that the axes of macromolecules in the grains are predominantly mutually parallel and the grains are oriented so 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 composite was studied.