The interest in biodegradable polymers has increased because of their environmental advantages. Blending them with other polymers is one of the techniques currently employed to overcome their brittleness, poor processing and cost. This work evaluated different blend compositions of PHB/PP, using a pro-degrading additive for this latter, to make the formulation prone to oxo-biodegradability in simulated soil (ASTM D6003). The mechanical, thermal and chemical behavior of buried injection molded tensile bars was monitored through measurements of tensile strength, DSC, FTIR, GPC and SEM. Part of the samples was oven aged at 90 ºC for 10 days in order to accelerate the PP oxidation by the additive. The blend made of 56 wt% of PP / 40 wt% of PHB / 3 wt% of GMA / 1 wt% of MnSt was the most susceptible to oxo-biodegradation, having reduced after 180 days of burring in soil, its tensile stress by 40%, tensile elongation by 46% and mass by 24%. These values were even higher than the ones for the pure PHB. This synergic effect was attributed to the acceleration of PHB degradation by the oxidized PP.
Poly-β-(hydroxybutyrate); polypropylene; blend; oxo-biodegradation; injection molding
