Palladium-catalyzed copolymerization to synthesize sulfur-containing polyethylene materials

Abstract

Direct copolymerization of ethylene with vinyl sulfur-containing comonomers has long posed challenges in achieving satisfactory results, thereby limiting the practical applications of sulfur-functionalized polyethylene materials. In this work, we designed and synthesized a series of norbornene-based comonomers containing sulfone, sulfonate, or thioanhydride groups. Their copolymerization with ethylene was investigated using phosphine–sulfonate palladium catalysts. These comonomers can afford remarkable copolymerization activities (up to 2.1 × 10⁶ g mol⁻¹ h⁻¹), high comonomer incorporation ratios (up to 29.0 mol%), and high molecular weights (up to 239 kg mol⁻¹). The resulting copolymers possess tunable thermal, mechanical, and surface properties. Moreover, copolymers containing sulfonate groups can be readily converted into sulfonic polyethylene, offering a convenient synthetic precursor.