Recyclable Multifunctional Copolyamide Elastomers via One-Pot Synthesis

Abstract

Thermoplastic polyamide elastomers have been widely used in many areas such as precision electronic components, automotive components, high-end sports equipment, and textile materials. Endowing these materials with multifunctionality at low cost remains a central challenge. This work reports a series of versatile block copolyamides (BCPAs) that integrate exceptional thermal stability, tunable melting points, and multiple advanced functions via low-cost one-pot synthesis. By incorporating a bio-based dimethylamino-caprolactam (DMACL) comonomer and employing an acid-catalyzed, amine-initiated polymerization approach involving terephthalic acid (PTA) and 1,6-hexanediamine (HDA), we successfully overcome the copolymerization barrier posed by basic tertiary amine groups in DMACL. This strategy enables precise tuning of the hard segment composition while ensuring full compatibility with the existing industrial polyamide 6 production process. The resulting BCPAs exhibit broadly tunable melting points (down to 101 °C), outstanding thermal stability with main-chain decomposition onset at 350 °C, and high visible-light transmittance (up to 90%). Additionally, they demonstrate an exceptional combination of functionalities, including intrinsic surface antistatic properties (107–1011 Ω) suitable for electronic applications, photoluminescence under 365 nm UV excitation, and effective UV-blocking capability. The polymers also feature controlled alcohol-soluble and water-insoluble behavior, facilitating green solution-based recycling. As a versatile post-polymerization modification platform, quaternization of the tertiary amine groups with dodecyl bromide yields materials with over 99% antibacterial activity against E. coli and S. aureus. This work provides a versatile platform for designing high-performance polyamides with tailored properties, with potential applications in protective coatings and biomedical materials.