Vanadium-Catalyzed Terpolymerization of α,ω-Dienes with Ethylene and Cyclic Olefins: Ready Access to Polar-Functionalized Polyolefins

Abstract

α,ω-Dienes are an important class of monomers due to their utility in the synthesis of cyclopolyolefins and reactive polyolefin intermediates. In this contribution, the terpolymerization of two α,ω-dienes (i.e., 1,5-hexadiene and 1,7octadiene) with ethylene and various cyclic olefins [i.e., norbornene (NB), 5ethylidene-2-norbornene (ENB), and dicyclopentadiene (DCPD)] catalyzed by a chelated imido vanadium complex has been examined. The ENB and DCPD diene termonomers provide additional sites for post-polymerization functionalization. Vanadium-catalyzed terpolymerization of the investigated α,ω-dienes yields polyolefins with a high molecular weight (M w up to 200 × 10 3 g mol −1 ), unimodal and narrow molecular weight distribution, subambient glass transition temperatures (−30 < T g °C < −3), and a proper content of CC bonds. Comprehensive NMR investigation of the obtained polymers revealed that subtle changes in the α,ω-diene size have important effects on the numerous combinations of insertion paths (ring closure vs ring opening), from which different repeating units with a CC bond in the side or main polymer chain and cyclic units are installed. Finally, the poly(ethylene-ter-1,5-hexadiene-ter-NB) was subjected to thiol-ene addition using thioglycolic acid, methyl thioglycolate, and N-acetyl-L-cysteine to access polar-functionalized polyolefins with a degree of functionalization and properties dependent on the thiol substitution.

Dynamically Cross-Linked Polyolefins via Hydrogen Bonds: Tough yet Soft Thermoplastic Elastomers with High Elastic Recovery

“…Scheme displays the manufacturing path of the crude polymer (named TP ) and of the functionalized polymers. The first step is the insertion terpolymerization of ethylene with HXD and NB catalyzed by V­(N–Ar py )­Cl 2 (NHMe 2 ) in combination with Et 2 AlCl as the cocatalyst (500 equiv to V) and in the presence of ETA as reoxidant (10 equiv to V) . The terpolymerization formed a soluble, solid polymer with high molecular weight ( M w = 158 × 10 3 g/mol) and narrow molecular weight distribution ( M w / M n = 2.0).…”

“…Thioglycolic acid (SH-Merck, 99%), methyl thioglycolate (SMe-Merck, 95%), Cys (Merck, 99%), 2,2′-azobis­(2-methylpropionitrile) (AIBN-Merck, 98%), and anisole (Merck, 99%) were used as received. V­(N–Ar py )­Cl 2 (NHMe 2 ) was prepared according to our published procedure …”

“…TP was functionalized with SH, SMe, and Cys via thiol–ene addition . In a typical reaction, 300 mg of TP were dissolved in 15 mL of anisole.…”

“…The modification of reactive polyolefin intermediates is a valuable approach to access functional P-TPEs, − alternative to the direct copolymerization of polar (co)­monomers. − Recently, we reported the synthesis of a well-defined polymer bearing reactive CC bonds and its chemical modification via thiol–ene addition . To follow up our preliminary investigation, herein, we report the optimization of synthesis conditions, and we demonstrate that the grafted thiol branches crosslink the polymer chains via hydrogen bonding.…”

Design and synthesis of binuclear vanadium catalysts for copolymerization of ethylene and polar monomers

“…10,11 Vanadium complexes are good candidates for nonpolar olefin polymerizations. [12][13][14][15][16][17][18] In particular, vanadium possesses lower oxophilicity than IVB transition metals. The Li group reported the catalytic behavior of vanadium complexes in the copolymerization of ethylene with polar comonomers, such as 10-undecen-1-ol and methyl 10-undecenoate.…”