Direct synthesis of polar functionalized linear low density polyethylene (LLDPE) using slow-chain-walking palladium catalysts

Abstract

Linear low-density polyethylene (LLDPE) is the most widely produced type of polyethylene resin. In this work, we detailed the synthesis and analysis of two bulky α-diimine Pd(II) complexes. These Pd(II) complexes can efficiently synthesize LLDPE-type polyethylene materials (ρ = 0.91–0.93 g/cm³) through ethylene slow-chain-walking polymerization. More interestingly, benefiting from the cationic bulky Pd(II) complexes, polar-functionalized LLDPEs (ρ = 0.91–0.92 g/cm³) are also produced by copolymerization of ethylene with various polar monomers such as 10-methyl undecanoate, methyl acrylate, 10-undecenoic acid. The copolymerization maintains the slow-chain-walking polymerization feature, resulting in a polar copolymer with a high melting point and low branching density. The results of ¹³C NMR spectral also reveal that polar groups are mainly located at the end of the branches in polar-functionalized LLDPEs.