3D-Printed, Ultrastretchable Polychloroprene Elastomers via Thiol-ene Photopolymerization

Polychloroprene is a foundational high-performance synthetic elastomer known for its exceptional chemical stability, resistance, and mechanical properties, making it useful in many important applications ranging from aerospace seals to medical devices. Despite its widespread use, polychloroprene is almost exclusively processed by using thermal cure agents. Herein, we report the first-ever successful ultraviolet (UV) curing and three-dimensional (3D) printing of polychloroprene networks. Leveraging thiol-ene click chemistry, solid polychloroprene was dissolved in a solvent and UV-cured with varied concentrations and architectures of thiol cross-linkers. Upon solvent evaporation, the resulting cross-linked polychloroprene networks exhibit ultrahigh extensibility, with strain at break values approaching 2000%. Significantly, their thermal properties show only marginal differences from those of the uncured material, confirming the preservation of the intrinsic polychloroprene characteristics. We demonstrate the potential of this new material platform using photorheology experiments, as well as successful 3D printing of complex objects using a commercial digital light processing (DLP) system. The printed articles exhibit mechanical properties fully comparable to conventionally processed, unfilled polychloroprene rubber, achieving an ultimate tensile stress of 2.4 MPa and a strain at break of 1200%. This work overcomes a significant processing barrier, offering an avenue to additively manufacture high-performance polychloroprene structures with exceptional mechanical resilience.