Thermal Decomposition and Kinetics of Mixtures of Polylactic Acid and Biomass during Copyrolysis

Thermal decomposition of polylactic acid (PLA) was studied in the presence of pine wood sawdust (PS), walnut shell (WS), corncob (CC) in order to understand the pyrolytic behavior of these components occurring in waste. A thermogravimetric analyzer (TGA) was applied for monitoring the mass loss profiles under heating rate of 10°C·min−1. Results obtained from this comprehensive investigation indicated that PLA was decomposed in the temperature range 300–372°C, whereas the thermal degradation temperature of biomass is 183–462°C. The difference of mass loss (ΔW) between experimental and theoretical ones, calculated as algebraic sums of those from each separated component, is about 17%–46% at 300–400°C. These experimental results indicated a significant synergistic effect during PLA and biomass copyrolysis. Moreover, a kinetic analysis was performed to fit thermogravimetric data, the global processes being considered as one to two consecutive reactions. A reasonable fit to the experimental data was obtained for all materials and their blends.