Highly resilient polyethylene elastomers prepared using α‐diimine nickel catalyst with highly conjugated backbone

Abstract

An α-diimine nickel catalyst (Cat-1) with highly conjugated acenaphthylene backbone was synthesized and used in ethylene polymerization. Compared with typical Brookhart catalyst B-Cat, Cat-1 could produce polyethylene with both higher molecular weight (up to 5.1 × 10 5 g mol −1 ) and branching density (up to 135 branches per 1000 carbons) in good polymerization activity. The polyethylene prepared using Cat-1 with higher molecular weight and branching density possessed exceptional mechanical properties (ultimate tensile strength and elongation at break could reach 12.08 MPa and 1148%) and outstanding elastomeric recovery as compared with the polymer prepared using B-Cat. Cat-1 was synthesized using a simple reaction route and the polymerization conditions were suitable for the industrial polymerization process. The novel nickel catalyst Cat-1 is promising for producing highly resilient polyethylene elastomers industrially.KEYWORDS α-diimine nickel catalyst, elastomeric recoverymechanical propertiespolyethylene elastomer

Synthesis and characterization of polyolefin thermoplastic elastomers: A review

“…At such high temperatures, it is of great challenge for the catalysts to maintain high activity while producing polymers having high molecular weights. [5,[33][34][35] It has been found that the CGC possesses a high copolymerization activity for α-olefin at high temperatures. [36] During the olefin copolymerization catalyzed by the methyl silicon-bridged CGC-Ti (A in Figure 4), the chain transfer to monomer results in the formation of vinyl-terminated macromonomers that can be readily inserted into the propagating chains in situ.…”

“…The type of branch structure is determined by the ratio of the chain walking rate to the chain propagation rate. [34,[55][56][57][58][59][60] It is worthy of note that such a ratio could be tuned by the catalyst structure and reaction conditions, such as pressure. Chen et al [55] synthesized α-diimine nickel catalysts with -Ph substituent (Ni-Ph), which catalyzed the ethylene polymerization to produce POEs (C in Figure 3).…”

Effect of N‐Aryl Para‐Benzhydryl Substituent on the Thermal Stability of α‐Diimine Nickel Catalyst

“…The branch DOI: 10.1002/marc.202300221 density of the product can be regulated by the modification of the catalyst structure and the adjustment of polymerization conditions, which has good application potential. [11][12][13][14][15][16] Over the past three decades, the modification of the catalyst structure has been the main research direction, such as the change in the N-aryl structure [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] or the backbone structure, [34][35][36][37][38][39][40][41][42][43][44] even the introduction of strong combination strategy. [45][46][47][48][49] Improving the catalyst thermal stability is what researchers are passionate about, which is related to the industrial application of catalysts, but there are few related pieces of research about the inactivation mechanism.…”