A METHOD OF CLOSED LOOP RECYCLING OF POLYLACTIC ACID

A process for chemically recycling polylactic acid (PLA), includes at least a first stage of depolymerisation of the PLA and a separate second consecutive stage of depolymerisation, to which stages the PLA is subjected in a continuous manner, wherein in the first stage, the PLA is continuously fed to an extruder operated at a temperature above the melting temperature of the PLA, while a water is co-fed to the extruder, in order to produce a fluid mixture including a melt of the at least partly depolymerised PLA, and in the second stage, the fluid mixture is continuously fed to a continuously stirred tank reactor (CSTR) operated at a temperature above the melting temperature of the PLA, while co-feeding water to the CSTR, wherein a residence time in the CSTR is used to provide at the outlet of the CSTR a continuous stream of PLA depolymerised into an oligomeric ester.