Synthesis of Hydroxy-Functionalized Polyethylene via Radical Copolymerization of Ethylene with Alkenyl Boronate and Post-Polymerization Oxidation.

Radical copolymerization of ethylene was performed with alkenyl boronate, and post-polymerization oxidation was conducted to synthesize hydroxy-functionalized polyethylene (PE). The copolymerization behavior was dependent on the molecular structure of the boron monomer: the copolymerization with α-methyl substituted monomer carrying boronic acid pinacol ester [isopropenylboronic acid pinacol ester (IPBpin)] afforded copolymers with higher molar masses than the vinyl-type monomer [i.e., vinylboronic acid pinacol ester (VBpin)]. The content of the boron-pendant units was up to 7 mol%, and kinetic studies suggested the incorporation of boron-pendant units in a discrete manner. The post-polymerization oxidation of the boron pendants on the copolymer proceeded quantitatively, affording a hydroxy-containing polyethylene. The introduction of a hydroxy group had a significant impact on the crystallization behaviors.