A Co-Anchoring Strategy for the Synthesis of Polar Bimodal Polyethylene

AbstractSince polar groups can poison the metal centers in catalysts, the incorporation of polar comonomers usually comes at the expense of catalytic activity and polymer molecular weight. In this contribution, we demonstrate polar bimodal polyethylene as a potential solution to this trade-off. The more-polar/more-branched low-molecular-weight fraction provided polarity and processability, while the less-polar/less-branched high-molecular-weight fraction provided mechanical and melt properties. To achieve high miscibility between these two fractions, three synthetic routes were investigated: mixtures of homogeneous catalysts, separately supported heterogeneous catalysts, and a co-anchoring strategy (CAS) to heterogenize different homogeneous catalysts on one solid support. The CAS route was the only viable strategy for the synthesis of polar bimodal polyethylene with good molecular level entanglement and minimal phase separation. This produced polyolefin materials with excellent mechanical properties, surface/dyeing properties, gas barrier properties, as well as extrudability and 3D-printability.