Direct Synthesis of Telechelic Polyethylene by Selective Insertion Polymerization

Abstract

A single-step route to telechelic polyethylene (PE) is enabled by selective insertion polymerization. Pd II -catalyzed copolymerization of ethylene and 2-vinylfuran (VF) generates a,w-di-furan telechelic polyethylene. Orthogonally reactive exclusively in-chain anhydride groups are formed by terpolymerization with carbic anhydride. Combined experimental and theoretical DFT studies reveal the key for this direct approach to telechelics to be a match of the comonomers different electronics and bulk. Identified essential features of the comonomer are that it is an electron-rich olefin that forms an insertion product stabilized by an additional interaction, namely a p-h 3 interaction for the case of VF.Telechelic polymers, composed of chains with two distinctive endgroups, are of broad relevance. They are used, for example, as cross-linkers, chain extenders, and to form block copolymers and defined networks.[1] Syntheses of telechelic polymers with well-defined structures from simple feedstocks such as ethylene are, however, rare. At the same time, telechelic polyethylenes (PEs) are finding increasing attention. They combine attractive properties such as crystallizability, chemical stability, a hydrophobic nature and compatibility with polyolefin materials. [2] Existing approaches to produce telechelic PE comprise: 1) partial hydrogenation of polybutadiene followed by ethenolysis (metathesis degradation with ethylene); [3] 2) ring-opening metathesis polymerization (ROMP) of cyclic olefins in the presence of a key chain transfer agent (CTA) containing reactive groups followed by functionalization and hydrogenation; [4] 3) living coordinative polymerization of ethylene using functionalized initiators followed by chainend-capping agent in the absence of ethylene; [5] 4) catalyzed chain growth (CCG) polymerization [6] of ethylene using the combination of a neodymium catalyst [7] and a well-designed di(10-undecenyl)magnesium as a CTA followed by treatment with iodine and then t

Emerging Palladium and Nickel Catalysts for Copolymerization of Olefins with Polar Monomers

“…They copolymerize ethylene with as urprisingly wide variety of polar monomers (both group A and group B monomers). [57] Chen and co-workers showed that the polymerization properties of phosphinesulfonate palladium and nickel catalysts can be improved by the introduction of ap olyethylene glycol unit. [53] However,t heir low activities and low copolymer molecular weights are some of the main limitations.Recently, Nozaki and co-workers showed that the copolymer molecular weights can be significantly increased using am enthyl substituent.…”

Polar‐Functionalized, Crosslinkable, Self‐Healing, and Photoresponsive Polyolefins

“…Recently, several palladium‐ and nickel‐based catalysts have been reported with these capabilities . For example, phosphine sulfonate and related palladium catalysts have been extensively studied and can copolymerize ethylene with various polar comonomers …”

“…[10][11][12][13][14][15][16] For example,phosphine sulfonate and related palladium catalysts have been extensively studied and can copolymerize ethylene with various polar comonomers. [17][18][19][20][21][22][23] In contrast to the numerous studies focused on catalyst development, fewer studies concerning the material proper-ties of polar-functionalized polyolefins,s uch as density, viscosity,s urface properties,d yeing properties,a nd mechanical properties,have been reported. [24][25][26][27][28][29] Moreover,the polar polyolefins in these studies were limited to thermoplastic-type materials.I n2 014, Mecking and co-workers reported the synthesis of polyolefins bearing siloxanes/glycidyl/anhydride groups via phosphine-sulfonate palladium-catalyzed copolymerizations.…”

Redox Control in Olefin Polymerization Catalysis by Phosphine–Sulfonate Palladium and Nickel Complexes

“…In addition to simple ligand modifications and developments, some alternative strategies have recently emerged. For example, Chen et al recently reported redox‐controlled olefin polymerization and copolymerization (Scheme , II ) , . In the phosphine–sulfonate Pd II catalysts, the installed ferrocene unit could be reversibly oxidized and reduced, leading to different reactivity towards olefin monomers.…”