The chemical recycling of poly(lactide) (PLA), especially the initial depolymerization step was studied. High molecular weight PLA was depolymerized in the presence of zinc catalyst to lactide, the industrial relevant chemical for the synthesis of high molecular weight PLA; therefore, an efficient recycling is feasible without the need for depolymerization reagents. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to ∼260 h−1 at 200–210 °C. Noteworthy, the lactide was isolated in high purity by reactive distillation. Furthermore, the zinc(II) acetate catalyst was recycled up to five times.

The chemical recycling of end‐of‐life plastics/polymers can contribute to a more sustainable society. In this regard, the selective degradation (depolymerization process) leading to well‐defined low molecular weight chemicals is a key feature of the chemical recycling. Based on that, we have investigated the depolymerization of end‐of‐life poly(lactide)‐based (PLA) goods. In more detail, applying a combination of methanol and catalytic amounts of 4‐dimethylaminopyridine (DMAP) end‐of‐life PLA was depolymerized to methyl lactate, a chemical which can be is used as “green” solvent or as starting material for new poly(lactide) products. With the assistance of microwave heating an excellent rate of depolymerization (>99%) was observed within short reaction times (10‐20 min). Interestingly, a set of 16 PLA commodities was efficiently transformed to methyl lactate.

The chemical recycling of end‐of‐life polymers, a sequence of depolymerization and polymerization reactions, enables the conserving of fossil resources and can add some value to the circular economy. In this study, a process for the depolymerization of end‐of‐life Nylon 6 via ring‐closing reactions to produce as building block N‐acetylcaprolactam have been set up. In detail, a combination of acetic anhydride as depolymerization reagent and catalytic amounts of 4‐dimethylaminopyridine allows under microwave irradiation and within short times (15 min) the conversion of end‐of‐life Nylon 6 to N‐acetylcaprolactam under solvent‐less conditions. Applying optimized conditions a sequence of Nylon 6 goods was transformed in good yields. The product N‐acetylcaprolactam was converted to ϵ‐caprolactam by transfer of the acetyl functionality to 2‐aminoethanol to give N‐(hydroxyethyl)acetamide a precursor for poly(N‐vinylacetamide). The generated ϵ‐caprolactam can be used as monomer for the synthesis of new Nylon 6, therefore a chemical recycling of the monomeric unit of Nylon 6 is feasible.

The depolymerisation of end-of-life poly(lactide) (PLA) goods was studied as part of the chemical recycling of PLA.