Facile Synthesis of Biobased, Low-Melting-Point Thermoplastic Polyamide Elastomer with Intrinsic Antibacterial Properties.

Thermoplastic polyamide elastomers (TPAEs) possess excellent elasticity and low-temperature resistance, making them suitable for a wide range of applications. However, the performance of commercial TPAEs relies on expensive and difficult-to-source polyamide-11 or polyamide-12 as the hard segment, which restricts their accessibility and increases production costs. In this study, a biobased TPAE was synthesized via simple successive ring-opening and condensation polymerization of inexpensive ε-caprolactam (ε-CL), biobased dimethyl-protected cyclic lysine (DMCL) pioneered by us, polyether, and a dibasic acid. The resulting elastomer exhibits excellent elasticity (elongation at break up to 1133%) that is retained even at low temperatures. The melting point of the hard segment could be tuned by varying the ε-CL molar ratio, reaching as low as 183.3 °C. Notably, an efficient multinuclear titanium (Ti4) catalyst facilitated the one-pot polycondensation even in the presence of high water content, yielding a product free of unreacted polyether. Additionally, the dimethylamino side groups impart intrinsic antibacterial properties to the elastomer. This unique combination of properties renders the developed TPAE highly attractive for high-value-added applications such as medical devices.