Renewable Lactam Monomer for Tunable and Processable Polyamides

Replacement of petroleum-derived
monomers with renewable
alternatives
is an integral part of the sustainable polymer framework. Research
in this area involves the search for bio-based or recycled starting
materials for traditional polymers, as well as investigations into
new materials accessible from renewable feedstocks. Focusing on the
latter, we studied the properties of polyamides synthesized from γ-methyl-ε-caprolactam
through anionic ring-opening polymerization by an activated monomer
mechanism. The amorphous homopolymer presents high stiffness (Young’s
modulus, ≈3 GPa), strength (stress at break, ≈80 MPa)
and toughness under dry (low humidity) conditions, high ductility
(strain at break, ≈1100%) in humid environments, optical clarity,
and excellent processability due to its non-crystallizable nature
and solubility in common organic solvents. Copolymerization with ε-caprolactam
allows tailoring the mechanical properties and crystallinity in the
resultant copolymers and provides new opportunities for advanced manufacturing
and other applications.