上海科技大学知识管理系统

The recycling of plastic waste has gained importance in reducing environmental pollution and optimizing resource utilization in recent years. A promising approach is the conversion of waste polyethylene (PE) into polyethylene waxes (PEW). In this work, waste agricultural film (WAF) was utilized as feedstock to produce PEW. The pyrolytic waxes obtained exhibited a viscosity-average molecular weight ranging from 2000 to 7000 g/mol, with a yield exceeding 95% between 380-410°C, a time period of 15 to 45 minutes, and at a ratio of 1:1 of decahydronaphthalene solvent to raw material. The reaction mechanism for the production of waxes during PE pyrolysis involved the generation, transfer, isomerization, recombination and dehydrogenation reactions of free radicals, which predominantly leads to the formation of PEW, accompanied by the generation of other small hydrocarbon molecules. Besides, the color formation of the waste film pyrolytic waxes with a whiteness of 19.8 was due to inorganic salts and organic compounds such as conjugated components and aromatics, and the pyrolytic waxes could be transformed into white with a whiteness of 85.4 through selective hydrogenation. © 2023