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<p>Single-step ethylene polymerization over a binary catalyst, including zirconocene precatalysts of various designs, has been studied to obtain polymer compositions based on ultrahigh-molecular-weight polyethylene (UHMWPE) and low-molecular-weight HDPE (LMWPE) directly in synthesis. Zirconocenes <i>rac</i>-(CH<sub>3</sub>)<sub>2</sub>SiInd<sub>2</sub> ZrCl<sub>2</sub> (<b>Zr-1</b>) and <i>rac</i>-(C<sub>6</sub>H<sub>10</sub>)CpIndZrCl<sub>2</sub> (<b>Zr-2</b>) activated with methylaluminoxane (MAO) were used as the components of the binary catalyst. It has been shown that the use of <b>Zr-1</b>/MAO and <b>Zr-2</b>/MAO in ethylene polymerization at 30 °C leads to the production of UHMWPE with <i>M</i><sub>w</sub>=1000 kg·mol<sup>-1</sup> and LMWPE with <i>M</i><sub>w</sub>=18 kg·mol<sup>-1</sup>, respectively. Reactor polymer compositions (RPC) with LMWPE fraction contents ranging from 9 wt% to 42 wt% were obtained when a molar fraction of <b>Zr-2</b> in the binary catalyst (<b>Zr-1</b>+<b>Zr-2</b>)/MAO varied in the range from 0.3 to 0.85. A study of the molecular weight characteristics of RPC showed that it has a wide bimodal molecular weight distribution (MWD) and includes UHMWPE (<i>M</i><sub>w</sub>=1000 kg·mol<sup>-1</sup>) and LMWPE (<i>M</i><sub>w</sub>=18 kg·mol<sup>-1</sup>) fractions. The degree of crystallinity of the polymer products was determined using the DSC method. The tensile properties and melt indices of the materials were studied depending on the LMWPE fraction content in the polymer composition. UHMWPE/LMWPE compositions with high tensile properties and fluidity at a load of 5 kg were obtained.</p>

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All Polyethylene Compositions Based on Ultrahigh Molecular Weight Polyethylene Synthesized Over Binary Catalyst Including Zirconocenes of Various Designs

  • 期刊论文

  • 发表日期：

    2025年10月11日

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  • Tatiana M. Ushakova,
  • Elena E. Starchak,
  • Sergey S. Gostev,
  • Sergey S. Gusarov,
  • Igor I. Arutyunov,
  • Vadim G. Krasheninnikov,
  • Aleksandr Z. Voskoboynikov,
  • Ludmila A. Novokshonova

摘要

Single-step ethylene polymerization over a binary catalyst, including zirconocene precatalysts of various designs, has been studied to obtain polymer compositions based on ultrahigh-molecular-weight polyethylene (UHMWPE) and low-molecular-weight HDPE (LMWPE) directly in synthesis. Zirconocenes rac-(CH3)2SiInd2 ZrCl2 (Zr-1) and rac-(C6H10)CpIndZrCl2 (Zr-2) activated with methylaluminoxane (MAO) were used as the components of the binary catalyst. It has been shown that the use of Zr-1/MAO and Zr-2/MAO in ethylene polymerization at 30 °C leads to the production of UHMWPE with Mw=1000 kg·mol-1 and LMWPE with Mw=18 kg·mol-1, respectively. Reactor polymer compositions (RPC) with LMWPE fraction contents ranging from 9 wt% to 42 wt% were obtained when a molar fraction of Zr-2 in the binary catalyst (Zr-1+Zr-2)/MAO varied in the range from 0.3 to 0.85. A study of the molecular weight characteristics of RPC showed that it has a wide bimodal molecular weight distribution (MWD) and includes UHMWPE (Mw=1000 kg·mol-1) and LMWPE (Mw=18 kg·mol-1) fractions. The degree of crystallinity of the polymer products was determined using the DSC method. The tensile properties and melt indices of the materials were studied depending on the LMWPE fraction content in the polymer composition. UHMWPE/LMWPE compositions with high tensile properties and fluidity at a load of 5 kg were obtained.