Co-pyrolysis behavior of polylactic acid and biomass from heated tobacco products

In this study, the co-pyrolysis behavior of waste tobacco (WT) and polylactic acid (PLA) from heated tobacco products (HTPs) was investigated by TG, TG-FTIR, and Py-GC/MS in order to reveal the synergistic mechanism during the co-pyrolysis process from the perspective of pyrolytic kinetic parameters and product distribution. The addition of WT during the pyrolysis of PLA reduced the T max from 367.5 to 303.8−314.1°C, indicating a notable synergistic effect between PLA and WT during the co-pyrolysis process. Pyrolysis kinetic analysis also indicated the enhanced thermal activity of PLA as reflected by the reduced activation energy, especially when the proportion of WT was wt. 25%, the activation energy was reduced from 166.38 to 111.20 KJ/mol. Meanwhile, the decreased ∆G for the co-pyrolysis of PLA/WT may also indicate an enhanced reaction reactivity. The pyrolytic products detected by TG-FTIR showed that the addition of WT-promoted free radical reactions during the co-pyrolysis process as reflected by the reduction of CO and aldehyde. Py-GC/MS results indicated that for PLA/WT= 1:1, the yield of lactide increased threefold, indicating a significant synergistic effect. In summary, the co-pyrolysis of PLA and WT could effectively tap into residual value from discarded HTPs in resource recovery field and solve potential environmental pollution problems.