Tailoring Branched Polyethylene with Polar Segments: A Strategic Approach to Multifunctional Polyolefin Materials.

A two-step synthetic strategy (combining coordination polymerization and radical polymerization) was developed to produce a novel kind of branched functional polyethylene (PE) with multiple polar segments (integrating block and branched architectures). Using a binuclear nickel catalyst, the copolymerization of ethylene with polar diene generates PE bearing methacrylate pendants (up to 4.62 mol %, 60/chain), which can serve as a macromolecular branching agent (PE branching agent). Subsequent radical copolymerization with methyl methacrylate (MMA) efficiently introduced PMMA segments into the PE backbone, yielding branched functional PE with highly tailored molecular weights (350-2300 kg/mol) and polar/nonpolar unit ratios (1/38-1/3 molar). The incorporation of PMMA segments confers a pronounced mechanical reinforcement effect, elevating the fracture strength from 6.18 to 19.64 MPa. The resultant material boasts mechanical properties on par with those of polar polyolefin elastomers (POEs) and exhibits versatile application capabilities, functioning both as a toughener for PMMA and as a compatibilizer for POE/PMMA blends.