Dispersion of TiO₂ Particles in PET/PP/TiO₂ and PET/PP/PP‐g‐MA/TiO₂ Composites Prepared with Different Blending Procedures

Abstract 2 vol.‐% TiO 2 particles were incorporated into PET/PP blends with and without MA‐grafted PP compatibilizer. During extrusion of the PET/PP/TiO 2 composites the TiO 2 particles migrated from the PP matrix to the PET‐dispersed phase irrespective of the blending route. For the PET/PP/PP ‐g‐ MA/TiO 2 composites, however, the location of TiO 2 depended on the blending sequence. The preferred location of the TiO 2 nanoparticles was confirmed by SEM pictures taken from the chemically etched surface of the blends. The observed migration behavior was traced to differences in the interfacial tensions between TiO 2 and PET and TiO 2 and PP, and to TiO 2 encapsulation in one of the blend components during the related blending procedure. magnified image