Emulsion Polymerization Strategy for Heterogenization of Olefin Polymerization Catalysts

Abstract

Heterogenization of homogeneous metal catalysts on solid supports has been widely studied for product morphology control in ethylene polymerization. In this contribution, an emulsion polymerization strategy was introduced to achieve heterogenization of various imino-based nickel olefin polymerization catalysts. A series of polymeric microspheres were prepared through emulsion copolymerization of vinyl-functionalized imino ligands with comonomers such as styrene or methyl methacrylate. The corresponding heterogeneous nickel catalysts demonstrated superior properties in ethylene polymerization and copolymerization with methyl 10-undecylenate. Their catalytic properties can be controlled by tuning the comonomer type, composition, and particle size. Most importantly, this strategy can achieve product morphology control and avoid reactor fouling while generating polyethylene products with minimum inorganic contamination. In addition, the introduction of polymer microspheres can improve the mechanical properties and surface properties of polyolefin products.

Heterogeneous Nickel Catalysts for the Synthesis of Ethylene-Based Polyolefin Elastomers

“…In contrast, Ni1 completely lost activity after 0.5 h at 140 °C. When the same amount of Ni2 (2 μmol) was loaded on a larger amount of MgCl 2 solid support (100 mg instead of the commonly used 66 mg; Table , entry 9 vs entry 7), a polymer product with a higher tensile strength was generated, which may be due to the reinforcing effect from the dispersed inorganic nanoparticles. , …”

“…When the same amount of Ni2 (2 μmol) was loaded on a larger amount of MgCl 2 solid support (100 mg instead of the commonly used 66 mg; Table 2, entry 9 vs entry 7), a polymer product with a higher tensile strength was generated, which may be due to the reinforcing effect from the dispersed inorganic nanoparticles. 46,47 Subsequently, the polymerization properties of Ni1@MgCl 2 at higher ethylene pressure and on a large scale were investigated. At 20 atm ethylene pressure, 120 °C, and in 900 mL of heptane, Ni1@MgCl 2 demonstrated activity of 3.25 × 10 6 g•mol −1 •h −1 and polymer molecular weight of 2.411 × 10 6 g• mol −1 (Table 2, entry 10; EPOE1).…”

Heterogenization Strategies for Nickel Catalyzed Synthesis of Polyolefins and Composites

“…In addition, these polymer-supported olefin polymerization catalysts can lead to good product morphology control. 55,59 Recently, inspired by the condensation nucleus of artificial rainfall, our group prepared core−shell type α-diimine nickel self-supported catalysts via in situ precipitation polymerization of the ionic cluster type polar monomer M1-Al (Figure 5I). 60 The catalysts were used in slurry and gas-phase polymerization of ethylene, resulting in high activity and good product morphology control.…”

“…Moreover, polyolefin composites containing polyolefin ionomer components showed improved mechanical properties and oxygen barrier properties (Figure H). In addition, these polymer-supported olefin polymerization catalysts can lead to good product morphology control. , …”

Lewis acid-induced homo- and heterogeneous nickel catalysts for ethylene polymerization and copolymerization with polar monomers

“…Heterogeneous catalysts are predominantly for industrial polyolefin production because they offer many distinct advantages, such as controlling the morphology of the polymer and preventing reactor fouling. [43][44][45][46][47][48][49][50][51] For instance, Rojas and Scott prepared heterogeneous [N, O]-and [N, N]-type nickel catalysts based on B(C 6 F 5 ) 3 or Al-modified supports for ethylene polymerization to improve catalytic activity (Scheme 1E and F). [52][53][54] Recently, Shiono and Cai et al prepared heterogeneous nickel catalysts via the reaction of an anilinonaphthoquinone ligand with methylaluminoxane-modified silica (MMAO/SiO 2 ).…”