Chunrui Rong,Dongxia Yan,Jiabao Li,Jian Feng,Jiayu Xin,Qing Zhou,Yi Li,Junli Xu,Xingmei Lu
The increase in the usage of polyethylene terephthalate (PET) leads to the generation of a large amount of waste, which may cause carbon emissions and waste of petroleum resources. The methanolysis method has attracted global attention, but limited by high reaction temperature and excessive use of methanol. We report here an efficient catalyst, tetramethylguanidine/1,5-diazabicyclo[4.3.0]-5-non-ene (TMG/DBN), converting waste PET into regenerated dimethyl terephthalate (rDMT) under 100 °C with almost equivalent methanol, achieving 100 % PET conversion and 93.1 % yield of rDMT. A series of analytical methods and theoretical calculations were used to reveal the enhanced interaction between the catalyst and reactants, which facilitates the degradation of PET at low methanol dosages. In addition, a kinetic model was also developed with a relatively low activation energy of 84.9 kJ/mol. This work provides an effective strategy for the up-grading recycling of waste PET under mild reaction conditions.
The effective recycling of waste polyurethane foam (PUF) is essential for reducing environmental burden, preventing littering, and decreasing reliance on virgin resources. In this study, we developed a mild, solvent-assisted glycolysis strategy using polyether polyol and various small-molecule diols to achieve complete depolymerization of waste PUF. The resulting recycled polyols (RPs) exhibited excellent reactivity and compatibility, enabling direct reuse-without purification-in the synthesis of rigid polyurethane foam (RPUF) at a substitution level of up to 40 wt%. Comprehensive characterization confirmed that the mechanical and physical properties of the recycled RPUF were comparable to those of commercial products. Importantly, a cradle-to-gate life cycle assessment (LCA) was conducted, highlighting the minimal differences in environmental impacts of the process, with a focus on the limitations of the assessment, particularly in terms of global warming potential (GWP). This work provides important theoretical support for the industrialization of polyurethane waste recycling.
危险品化学品经营许可证（带存储）