Synthesis of Ultrahigh-Molecular-Weight Ethylene-1-Hexene Copolymers with High Hexene Content via Living Polymerization with Fluorinated Bis(phenoxy-imine) Titanium(IV)

Abstract

The fluorinated FI-Ti catalyst bis[N-(3-propylsalicylidene)-pentafluoroanilinato] titanium(IV) dichloride (PFI) combined with dried methylaluminoxane (dMAO) is investigated for ethylene/1-hexene copolymerization at 50 °C under atmospheric pressure. The reaction shows good livingness and has a high activity at high [H]/[E] molar ratios up to 14. Ultrahigh molecular weight (>1.4 × 10(6) g mol(-1) ) copolymers with high 1-hexene content (>25 mol%) are prepared. Kinetic parameters of the copolymerization with PFI are determined. The first-order Markov statistics applies and the product of the reactivity ratios r1 r2 is close to 1, giving random unit distributions.

Improving 1-Hexene Incorporation of Highly Active Cp–Chromium-Based Ethylene Polymerization Catalysts

“…Therefore, a highly active catalytic system has been developed, which allows the efficient production of UHMW-PE with high comonomer content. To the best of our knowledge only one catalytic system has been described so far which allows the production of similar ethylene 1-hexene copolymers (with similarly high molecular weights) . However, the nonliving nature of the catalysts reported here combined with their much higher catalytic activity renders them ideal candidates for improved hybrid-catalysts leading to multimodal polyethylene composite materials. − …”

“…1-Hexene can be obtained in situ by selective trimerization of ethylene. − The comonomer contend in ethylene/α-olefin copolymers has a big influence on the crystallinity and therefore on the microscopic structure and on the mechanical properties of the polymer. , In general the melting point, the crystallinity and the density is lowered by short chain branches resulting in a higher flexibility and a better processability . Ethylene propylene copolymers with ultrahigh molecular weight and recently also UHMW-PE with a 1-hexene content of over 25 mol % have been synthesized with bis­(phenoxy-imine)­titanium­(IV) catalysts. − However, the living polymerization behavior of these catalysts lead to a dependence of the polymer property on polymerization time which is often undesired especially in applications with multicomponent catalysts.…”

Research Progress of Pre - transition Metal Olefin Polymerization Catalyst for Salicylaldehyde Imine

“…Liu et al [29] synthesized the catalyst 47 which can catalyze the copolymerization of ethylene / 1-octene to produce an ultrahigh molecular weight copolymer with a 1-octene insertion amount of up to 32.7%. Guo et al[30] synthesized the catalyst 48 used to catalyze the copolymerization of ethylene / 1-hexene.…”

Synthesis of ultrahigh-molecular-weight ethylene/1-octene copolymers with salalen titanium(iv) complexes activated by methyaluminoxane

“…20 Since then many new CGC and post metallocene catalysts have been designed and developed, especially many group IV transition metal complexes bearing O, N -chelating or N , N -chelating ligands exhibited surprisingly excellent catalytic performance on the copolymerization of ethylene with α-olefin, and made significant improvement on the polymer molecular weight and comonomer content. 8,21–25…”

“…20 Since then many new CGC and post metallocene catalysts have been designed and developed, especially many group IV transition metal complexes bearing O,N-chelating or N,N-chelating ligands exhibited surprisingly excellent catalytic performance on the copolymerization of ethylene with a-olen, and made signicant improvement on the polymer molecular weight and comonomer content. 8,[21][22][23][24][25] The salalens are tetradentate [ONN 0 O]-type ligands can be regard as half-salan/half-salen, raping the metal center in a facmer mode with perfect octahedral structure. 26,27 Salalen type complexes exhibit amazing catalytic performance on various reactions like ring-opening polymerization, asymmetric oxidations, epoxide-CO 2 polymerization and a-olen homopolymerization.…”