Synthesis of Heterobifunctional Hyperbranched Polyethylenes Tethered with Dual Acryloyl and 2‐Bromoisobutyryl Functionalities via One‐Pot Chain‐Walking Terpolymerization

Abstract

A one‐step synthesis of heterobifunctional hyperbranched polyethylenes covalently tethered with dual acryloyl and 2‐bromoisobutyryl functionalities at controllable contents is reported. It is achieved in one pot by chain‐walking terpolymerization of ethylene with two functional acrylate comonomers, 1,6‐hexanediol diacrylate and 2‐(2‐bromoisobutyryloxy) ethyl acrylate. The unique chain‐walking mechanism renders the hyperbranched polymer chain topology and its remarkable capability in incorporating acrylate comonomers enables the incorporation of both comonomers to give two valuable functionalities. The two comonomers exhibit nearly equal vinyl reactivity and are incorporated independently in the terpolymerization with their molar contents controlled by adjusting the comonomer feed concentrations. magnified image

Palladium and Nickel Catalyzed Chain Walking Olefin Polymerization and Copolymerization

“…Copolymerization of ethylene with 1,4-butanediol diacrylate ( comonomer 3 ) can lead to functionalized hyperbranched polyethylene containing both cross-linked structure and pendant vinyl groups at low comonomer concentration . Heterofunctionalized hyperbranched copolymers were generated from the ethylene copolymerization with functional comonomer 4 and comonomer 5 . Interestingly, hyperbranched polyethylenes containing covalently tethered polyhedral oligomeric silsesquioxane (POSS) nanoparticles could be synthesized by chain walking ethylene copolymerization with a POSS containing comonomer 6 .…”

“…53 Heterofunctionalized hyperbranched copolymers were generated from the ethylene copolymerization with functional comonomer 4 and comonomer 5. 54 Interestingly, hyperbranched polyethylenes containing covalently tethered polyhedral oligomeric silsesquioxane (POSS) nanoparticles could be synthesized by chain walking ethylene copolymerization with a POSS containing comonomer 6. 55 The aggregation/interaction of the POSS nanoparticles enabled the observation of gel-like rheological behaviors.…”

Hyperbranched polyethylenes by chain walking polymerization: synthesis, properties, functionalization, and applications

“…Differently, Ye et al employed various functional acrylate comonomers (22,(32)(33)(34) in Scheme 11) for the synthesis of functionalized HBPEs containing different functionalities through ethylene copolymerization with catalyst 1. 46,[50][51][52][53] With 32 containing a polyhedral oligomeric silsesquioxane (POSS), they synthesized organic-inorganic hybrid materials with organic HBPEs tethered with inorganic POSS nanoparticles at contents up to 35 wt%. Due to the assembling feature of the tethered POSS nanoparticles to form small crystallites, these hybrid materials were demonstrated to have interestingly reinforced thermal and rheological properties.…”

“…52 Furthermore, through terpolymerization of ethylene with both 1,6-hexanediol diacrylate (a longer analogue of 22) and 33, Ye et al further synthesized HBPEs containing dual acryloyl and 2-bromoisobutyryl functionalities at controllable ratios. 53 In all functionalized polymers synthesized through copolymerization, the functionalities are all incorporated as side groups or branch ends, with their contents controlled by changing comonomer concentration in copolymerization. Their incorporation often has no or little effect on polymer chain topology and branching distribution as they are not located on the polymer backbone, i.e., the chain walking passage of the catalyst.…”

“…However, their incorporation often leads to reduced catalyst activity and polymer molecular weight as the comonomers are generally less reactive compared to ethylene. [50][51][52][53] In addition to the copolymerization strategy, Ye et al have also demonstrated the synthesis of telechelic HBPEs containing different u-end functionalities by quenching/end-capping ethylene ''living'' polymerization catalyzed with 5 using styrene derivatives. 54 This employs the unique inhibitive reaction of styrene derivative with cationic Pd-diimine species to form stable p-benzyl intermediate complexes, which are inactive for ethylene polymerization.…”