Eugenol and Chavicol-Based Polyamides from Synthesis to Degradation: Moving Towards Closing the Circle

A new series of polyamides (PAs) have been successfully prepared employing two phenolic natural compounds, eugenol and chavicol, as starting compounds. The synthesis has been carried out through a solvent free protocol using the environmentally friendly organocatalyst TBD. The so obtained materials have been properly characterized. Moreover, the prepared materials, all of them amorphous, showed a wide range of transition temperatures (Tgs) depending on the structure of the diester counterpart used in the polymerization reaction. The synthetized PAs demonstrated excellent thermal stability and dimensional integrity. Furthermore, the obtained polymers could be depolymerized under alkaline hydrolysis conditions, yielding, with good to excellent recovery ratios, the corresponding starting diamine monomer which could eventually be used in the synthesis of new polymers. This closed-loop chemical recycling represents a sustainable alternative to the end of use matter of discarded polymers and a pathway towards solving the problem of PA waste accumulation.