Investigation on the synergistic effect between different components in pyrolysis of paper-plastic composite material.

Pyrolysis characteristics of Tetra Pak, a paperboard-polyethylene-aluminium foil, were investigated in this study with a focus on the synergistic effect between its individual components. Scanning electron microscopy analysis indicated that molten LDPE coating on cellulose surface led to suppression on mass and heat transfer and the increased activation energy of pyrolysis reaction. Samples of individual components and simulated Tetra Pak packaging were pyrolyzed in a thermogravimetric analyzer at various heating rates. Synergistic effect between cellulose and LDPE on E a and the formation of characteristic products are investigated: Kinetic analysis showed that the cellulose decomposition peak in the simulated mixture exhibited a higher E a than that of pure cellulose at each conversion rate. For LDPE, the free radicals formed from cellulose pyrolysis enhanced the degradation of plastic polymers, resulting that E a of its decomposition peak in the mixture being lower in comparison to pure LDPE, with a discrepancy of around 16–27 kJ·mol−1. The formation of characteristic products including levoglucosan, furfural, 5-hydroxymethylfurfural, and alkanes from pyrolysis of cellulose and LDPE mixture with different mass ratios was further investigated in a micro-pyrolyzer. The results suggested that synergistic effects and physical barrier existed during fast pyrolysis between cellulose and LDPE. The extent of the synergy effect depended on the proportion of cellulose and LDPE in the mixture. • Synergistic effect was investigated during pyrolysis of Tetra Pak. • Molten LDPE coating on cellulose increases E a of cellulose pyrolysis. • The extent of synergy effect depends on the proportion of cellulose and LDPE. [ABSTRACT FROM AUTHOR]