Ultrafast microwave assisted recycling of PET to a family of functional precursors and materials

Abstract

A series of terephthalamides were successfully produced by rapid catalyst-free microwave-assisted aminolysis of polyethylene terephthalate (PET). The produced terephthalamides from chemical recycling of PET were further utilized as reactants for fabrication of plastic films by a radical thiol-ene reaction or they were evaluated as plasticizers for polylactide (PLA). The chemical recycling by aminolysis was performed with four different amines: allylamine, ethanolamine, furfurylamine or hexylamine. The microwave-assisted process led selectively to good yields of well-defined terephthalamides with different terminal functional groups depending on the used amine. The reaction time varied from 10 to 60 min. The end-product obtained after aminolysis with allylamine was further reacted with a thiol through a radical thiol-ene reaction, producing good quality films with glass transition temperature (Tg) above room temperature. The three other terephthalamides were mixed with PLA at 10 wt% and evaluated as plasticizers. The terephthalamide produced by aminolysis with furfurylamine, increased the strain at break 20 times compared to the strain at break of neat PLA. The results illustrate that chemical recycling of PET by aminolysis is a viable and versatile option, producing a library of valuable chemical compounds ready for further use in material applications.