Controlled Hydrogenation of Styrene-Butadiene Copolymers Using Tetralin as a Liquid Organic Hydrogen Carrier

Hydrogenation of unsaturated polymers is a powerful strategy to enhance mechanical and thermal performance, but conventional methods rely on high-pressure hydrogen systems. Here, we report a safe and sustainable approach using 1,2,3,4-tetrahydronaphthalene (tetralin) as a liquid organic hydrogen carrier (LOHC) for catalytic transfer hydrogenation of butadiene-based polymers—including styrene–butadiene–styrene (SBS), polystyrene-b-polybutadiene (PS-b-PB), styrene–butadiene rubber (SBR), and polybutadiene (PBD)—under ambient pressure. Using readily available carbon-supported metal catalysts, particularly Pt/C, we achieved tunable partial hydrogenation without molecular hydrogen, yielding elastomers with substantially improved tensile strength, toughness, and thermal stability. Critically, intermediate hydrogenation (~50%) enabled efficient sulfur crosslinking and robust network formation, underscoring the functional importance of controlled saturation. These results demonstrate tetralin as an effective liquid hydrogen donor, providing a scalable and sustainable alternative to high-pressure hydrogenation and expanding LOHC applications to advanced elastomer design.