Investigation of zeolite H-β effect on pyrolysis of polystyrene by multiple kinetic analysis methods

For studying the effects of H-β zeolite on the pyrolysis of polystyrene (PS), non-isothermal thermogravimetric measurements were conducted in N₂ under 5, 10, 15, and 20 K/min. The results show that the addition of 10 ~ 30 wt.% H-β zeolite can significantly decrease the initial pyrolysis temperature of PS, indicative of the catalytic effect of zeolite used. Through kinetic analysis of the pyrolysis of PS blends, the isoconversional activation energies are calculated to be 121.8 ~ 191.9, 92.1 ~ 173.8, and 116.7 ~ 192.4 kJ/mol for the PS blends with zeolite loading of 10, 20, and 30 wt.%, respectively. Meanwhile, the pyrolysis degradation functions are determined through the Master-plots method integrated with a recently developed compensation-effect method to follow chemical reaction mechanism with the reaction order of 0.9, 1.0, and 0.6 for PS/zeolite blends of 10, 20, and 30 wt.% loading, and their pre-exponential factors are respectively calculated to be 6.18 × 10⁸ ~ 5.71 × 10¹¹, 2.36 × 10⁶ ~ 9.23 × 10¹¹, and 8.38 × 10⁷ ~ 1.11 × 10¹² min^-1. Our work may provide some insights for how to better describe experimental results with theoretical predications and necessary information for performing any potential pyrolysis designs.