Heterogeneous α‐Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

Abstract

More importantly, the structure and properties of the polymer products can be controlled by catalyst structures, polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

Positional heterogenization effect in salicylaldimine nickel catalyzed ethylene polymerization

“…These trends are similar to those reported in the literatures. 49,53 Heterogeneous pre-catalysts Ni1@SiO 2 and Ni2@SiO 2 can catalyze ethylene polymerization under the same polymerization conditions as their homogeneous simulants Ni1 and Ni2 (Table 2, entries 1-5), resulting in high activities (up to 3.5 Â 10 6 g mol À1 h À1 ) and high molecular weights (up to 67 kg mol À1 ). It was shown that the positions of the anchoring groups have significant effects on catalytic performances.…”

“…Interestingly, some recent reports show that heterogenization effect may significantly improve the catalytic performances of various nickel-based olefin polymerization catalysts (Chart 1a,H-K). 3,22,[46][47][48][49] This is due to the influences of heterogenization on the steric hindrance and electronic effects of the catalysts.…”

Outer‐Shell Self‐Supported Nickel Catalysts for the Synthesis of Polyolefin Composites

“…The introduction of polar functional groups can significantly enhance the compatibility of polyolefins with polar components, thereby contributing to the preparation of high‐performance composites both in the melt blending process and in the in situ polymerization route [3–7, 31–33] . However, the typical heterogenization route remains largely unexplored in late transition metal olefin polymerization catalyst systems [7, 34–41] . In order to achieve high polymerization activity and universal applicability to different fillers, it is often necessary to synthesize new catalysts bearing specific anchoring groups (Figure 1C, right) [7, 34–43] .…”

“…[3][4][5][6][7][31][32][33] However, the typical heterogenization route remains largely unexplored in late transition metal olefin polymerization catalyst systems. [7,[34][35][36][37][38][39][40][41] In order to achieve high polymerization activity and universal applicability to different fillers, it is often necessary to synthesize new catalysts bearing specific anchoring groups (Figure 1C, right). [7,[34][35][36][37][38][39][40][41][42][43] Furthermore, catalyst performances may be significantly altered due to the interaction of the support with the catalyst at the molecular level, resulting in poor predictability.…”

“…[7,[34][35][36][37][38][39][40][41] In order to achieve high polymerization activity and universal applicability to different fillers, it is often necessary to synthesize new catalysts bearing specific anchoring groups (Figure 1C, right). [7,[34][35][36][37][38][39][40][41][42][43] Furthermore, catalyst performances may be significantly altered due to the interaction of the support with the catalyst at the molecular level, resulting in poor predictability. [1,14,35,[40][41][42][43][44][45] It may also result in significant decreases in (co)polymerization activity, molecular weight, and comonomer incorporation ratio.…”