Sustainable Chiral Polyamides with High Melting Temperature via Enhanced Anionic Polymerization of a Menthone-Derived Lactam

Polyamides are very important polymers that find applications from commodities up to the automotive and biomedical sectors, and their impact is continuously growing. The synthesis of structurally significant, chiral, and sustainable polyamides is described via a new, convenient, and solvent-free anionic polymerization of a biobased epsilon-lactam, which is obtained from the renewable terpenoid ketone L-menthone in a one-step synthesis. These polyamides are shown to have outstanding structural and thermal properties, which are thus introduced via the structure and chirality of the natural lactam monomer and which are discussed and compared with those of petroleum-based, established, and commercial polyamide Nylon-6. X-ray data reveal a remarkable degree of crystallinity in these green polymers and emphasize the impact of their structural features on the resulting properties.