Modulating polyolefin properties through the incorporation of nitrogen-containing polar monomers
In this work, ethylene copolymerization and terpolymerization reactions with some nitrogen-containing monomers were investigated using α-diimine palladium and phosphine-sulfonate palladium catalysts. In the α-diimine palladium system, ligand sterics plays an important role and sterically open ligands lead to much better comonomer incorporation. The phosphine-sulfonate palladium catalysts showed much better activities and higher copolymer molecular weights. Copolymers and terpolymers with high molecular weights but significantly different microstructures were obtained in these two systems. The incorporation of polar functionalized comonomers could significantly improve the surface properties of the resulting polymeric products. The water contact angle of pure polyethylene could be reduced from above 100° to ca. 80°. In addition, the mechanical properties of the polyolefins could be modulated by the introduction of these polar monomers.