Influence of hydrogen-donating solvents on liquefaction of polystyrene into fuel

The increasing polystyrene (PS) waste accumulation presents a significant environmental challenge. This study investigates the liquefaction of PS using hydrogen-donating solvents such as ethanol, decalin, and tetralin to convert plastic waste into valuable liquid fuels. This research examines the effects of temperature, reaction time, and solvent type on product yield and quality. Optimal conditions were found at 380 °C and 30 min, with decalin achieving the highest liquid yield of 88.94 %. Hydrogen-donating solvents significantly improved conversion rates, liquid product distribution, and reduced oxygen content compared to non-hydrogen-donating solvents. Mechanistic analysis shows these solvents stabilise free radicals and promote secondary reactions, enhancing product quality. The functional group and carbon chain composition of PS liquefied oil is consistent with those of gasoline and diesel, highlighting its potential as a fuel oil. The results underscore the effectiveness of hydrogen-donating solvents in optimising PS liquefaction, suggesting a promising approach for sustainable plastic waste management. Future research should explore the environmental and economic feasibility of large-scale PS liquefaction and its application to other plastic types.