Chain-Length-Accelerated Polyacrylate Deoxygenation for Functional Polypropylene

Post-polymerization modification is a powerful route to functional polyolefins that are difficult to synthesize by direct copolymerization. However, catalytic transformations of polymer substrates are often limited by steric congestion. Here, we show that the length of polymer affects the kinetics of borane-catalyzed deoxygenation of poly(methyl acrylate) (PMA), enabling access to hydroxyl-functionalized polypropylene (PP). The reaction rate increases with the degree of polymerization, indicating that longer PMA chains can accelerate catalytic post-polymerization transformation. This behavior is attributed to the higher effective local concentration of ester groups experienced by borane along longer polymer chains, which increases catalyst association with the polymer chains. Under these conditions, high-molar-mass PMA and PMA-containing copolymers can be efficiently converted into PP-based functional materials with tunable thermal and interfacial properties through controlled partial deoxygenation. These findings reveal how intrinsic polymer-chain characteristics can be used to enhance catalytic post-polymerization transformations.