Mineralization of Poly(lactic acid) (PLA), Poly(3-hydroxybutyrate-co-valerate) (PHBV) and PLA/PHBV Blend in Compost and Soil Environments

The present study investigates the mineralization of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-valerate) (PHBV), and PLA/PHBV blend in compost and soil burial environments. The mineralization was assayed on the basis of carbon dioxide (CO2) release from the test materials incubated in compost and soil for a period of 200 days. The degradation was followed by means of fragmentation, thermogravimetric (TGA), FTIR spectroscopy and scanning electron microscopy (SEM) analyses. The results showed that PLA, PHBV and blend of PLA/PHBV achieved almost 90% biodegradation under composting conditions, while PHBV, PLA/PHBV blend and PLA respectively achieved only 35%, 32% and 4% biodegradation under soil burial conditions. The results of crystallinity, thermal degradation, microstructure and surface morphology analyzed by TGA, FTIR and SEM indicated that the blending approach and different environmental conditions in soil and compost were the most influencing parameters for the ultimate biodegradation of these biobased polymers.