Direct Synthesis of Polyethylene Thermoplastic Elastomers Using Hybrid Bulky Acenaphthene-Based α-Diimine Ni(II) Catalysts

Hui Wang; Weiqing Lu; Mingmin Zou; Shengyu Dai

doi:10.3390/molecules28052266

Direct Synthesis of Polyethylene Thermoplastic Elastomers Using Hybrid Bulky Acenaphthene-Based α-Diimine Ni(II) Catalysts

Molecules. 2023 Feb 28;28(5):2266. doi: 10.3390/molecules28052266.

Authors

Hui Wang¹, Weiqing Lu^{2

3}, Mingmin Zou³, Shengyu Dai^{2

3}

Affiliations

¹ School of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China.
² School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu 241000, China.
³ Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.

Abstract

Recently, polyolefin thermoplastic elastomers can be obtained directly using ethylene as a single feedstock via α-diimine nickel-catalyzed ethylene chain walking polymerization. Here, a new range of bulky acenaphthene-based α-diimine nickel complexes with hybrid o-phenyl and -diarylmethyl anilines were constructed and applied to ethylene polymerization. All the nickel complexes under the activation of excess Et₂AlCl exhibited good activity (level of 10⁶ g mol^-1 h^-1) and produced polyethylene with high molecular weight (75.6-352.4 kg/mol) as well as proper branching densities (55-77/1000C). All the branched polyethylenes obtained exhibited high strain (704-1097%) and moderate to high stress (7-25 MPa) at break values. Most interestingly, the polyethylene produced by the methoxy-substituted nickel complex exhibited significantly lower molecular weights and branching densities, as well as significantly poorer strain recovery values (48% vs. 78-80%) than those by the other two complexes under the same conditions.

Keywords: branched polyethylenes; ethylene polymerization; polyethylene thermoplastic elastomers; α-diimine nickel complexes.

Abstract

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