Polypropylene (PP) has a slow natural degradation rate. On the other hand, poly(hydroxybutyrate) (PHB) is biodegradable but has the disadvantages of cost and difficulty of processing. The aim of this work was to evaluate the effect of TiO2 nanoparticles, processing conditions and accelerated aging on the structure and properties of PP/PHB/TiO2 mixtures. Samples were prepared by extrusion and injection molding. The incorporation of 3% TiO2 nanoparticles led to an increase in the average size of the dispersed phase rich in PHB. Changes in the sequence of TiO2 nanoparticles incorporation were able to guide the inclusion of nanoparticles to the PP-rich phase. The produced composites were more thermally stable than pure PHB and the incorporation of TiO2 was effective to increase the thermal stability of the composites. Thermal and FTIR analyses showed that blends containing TiO2 nanoparticles had their degradation more affected by accelerated aging treatments. Solvent extraction results revealed that a larger amount of soluble products from the photodegradation could be extracted from samples containing TiO2 submitted to accelerated aging treatments.
Polypropylene (PP); poly(β-hydroxybutyrate) (PHB); composites; TiO2
