Synthesis and Characterization of Terpenoid-derived Poly(6,10-dimethyl-1,3,9-undecatriene): A Biobased and Sustainable Polymer from Renewable Citronellal

As a naturally occurring terpenoid that is abundant in essential oils, citronellal remains largely unexplored in polymer science. Herein, we present a novel strategy for converting bio-based citronellal into the diene monomer 6,10-dimethyl-1,3,9-undecatriene (DMUT), which undergoes neodymium-catalyzed coordination polymerization to yield poly(6,10-dimethyl-1,3,9-undecatriene) (PDMUT), a bio-derived polydiene polymer. This provides a facile and sustainable route for transforming renewable citronellal into functional polymers. The effects of polymerization conditions on the catalytic performance and polymer characteristics, including molecular weight, polydispersity, and microstructure, were systematically investigated. In addition, DMUT was successfully copolymerized with isoprene (IP) and 1,3-butadiene (BD), yielding copolymers with tunable compositions and microstructures. These results demonstrate the versatility of DMUT as a renewable building block for both homopolymers and copolymers, paving the way toward bio-based elastomeric materials with customizable properties.