Synthesis of Functional Metallocene Polyethylene through Masking Free Copolymerization of Polar Monomer with Ethylene

Metallocene polyethylene (mPE) is a high-performance
polyolefin
that is renowned for its exceptional material properties. Although
polar functionalization of mPE can improve surface characteristics
and expand its applications, conventional synthesis methods face challenges
due to the poisoning effect of polar monomers on metallocene catalysts.
In this study, we present a direct metallocene-catalyzed copolymerization
of ethylene with oxygen- and nitrogen-containing polar monomers bypassing
the need for masking reagents. Integrated experimental and computational
analyses reveal that heteroatom interactions with the metallocene
center do not deactivate the catalyst; rather, they fine-tune copolymerization
behavior, influencing monomer insertion rates, catalytic activity,
and molecular weight. Using titanocene [Ti(Cp)2Cl2], we synthesized ethylene/anisyl propylene (AP) copolymers with
adjustable polar monomer incorporation (0–32 mol %). Meanwhile,
a zirconocene catalyst [Zr(CpMe5)2Me2] produced high-molecular-weight functional plastics (e.g., 4.5 mol
% AP, Mn = 370 kDa). The resulting polar
mPE copolymers exhibited tailored surface and mechanical properties,
highlighting their potential as advanced polyolefin-based adhesives
and engineered plastic materials.