Catalytic strategies for synthesizing disentangled ultrahigh molecular weight polyethylene via homogeneous FI catalyst-based polymerization

Lei  Li

doi:10.59400/mtr3164

Catalytic strategies for synthesizing disentangled ultrahigh molecular weight polyethylene via homogeneous FI catalyst-based polymerization

Lei Li SINOPEC Nanjing Research Institute of Chemical Industry Co., Ltd., Nanjing 210048, China; China Petroleum and Chemical Corporation, Beijing 100728, China; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China

Article ID: 3164

DOI: https://doi.org/10.59400/mtr3164

Keywords: dis-UHMWPE; FI catalyst; homogeneous catalyst; entanglement; single-site catalysis

Abstract

Ultrahigh molecular weight polyethylene (UHMWPE) is a high-performance polymer renowned for its exceptional mechanical strength, wear resistance, and chemical stability, making it indispensable in medical, industrial, and protective applications. However, its highly entangled molecular structure severely limits processability due to its extreme melt viscosity. Recent advancements in homogeneous catalyst-based polymerization, particularly using bis(phenoxyimine) titanium (FI) catalysts, have enabled the synthesis of disentangled UHMWPE (dis-UHMWPE), offering a breakthrough in overcoming these challenges. FI catalysts exhibit unique advantages, including living polymerization behavior, single-site homogeneity, and tunable steric/electronic effects, allowing precise control over molecular weight, narrow polydispersity, and reduced entanglement density. These features facilitate solvent-free solid-state processing, significantly improving melt processability while enhancing mechanical properties compared to conventional Ziegler-Natta (Z-N) catalyst-derived UHMWPE. Notably, key strategies such as low-temperature polymerization, cocatalyst modification, and optimized reaction kinetics when using an FI catalyst further ensure controlled chain propagation and crystallization, minimizing entanglements. This review highlights the transformative potential of FI-catalyzed dis-UHMWPE, including its inherent properties, advantages, and technical implementation details, in the preparation of dis-UHMWPE, setting a new benchmark for sustainable and high-performance polyolefin materials.

Published

2025-06-03

How to Cite

Li, L. (2025). Catalytic strategies for synthesizing disentangled ultrahigh molecular weight polyethylene via homogeneous FI catalyst-based polymerization. Materials Technology Reports, 3(1), 3164. https://doi.org/10.59400/mtr3164

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Issue

Vol. 3 No. 1 (2025)

Section

Review

This work is licensed under a Creative Commons Attribution 4.0 International License.

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In this study, Zr-doped HfO₂ (HZO) based resistive random-access memory (RRAM) device were fabricated. The Hf:Zr (1:1) ratio in the HZO films were controlled by changing the HfO₂ and ZrO₂ cycle ratio during the atomic layer deposition (ALD) process. Next, we studied the structural and electrical properties of the Au/HZO/TiN RRAM device structure. The RRAM devices exhibits an excellent resistance ratio of the high resistance state (HRS) to the low resistance state (LRS) of ~10 3 A, and as well as good endurance (300 cycles) and retention (>10 3 s), respectively. Further, the device showed different conduction mechanism in LRS and HRS modes. The lower biased linear region is dominated by ohmic conductivity, whereas the higher biased nonlinear region is dominated by a space charge limited current conduction. This device is suitable for application in future high-density nonvolatile memory RRAM devices.

Solid oxide fuel cells (SOFCs) are renowned for being effective energy sources that have potential to influence how energy is developed in future. SOFCs operate at low temperatures provides different benefits for widespread commercialization. In the present study a perovskite material Pr_0.6 Sr_0.4 Fe_0.8Co_0.2 O₃−δ (PSFCo) was investigated as cathode for SOFC in intermediate temperature range. Glycine nitrate process was used for the preparation of the samples. PSFCo exhibited cubic structure having small particle size (100–200 nm). The electrical conductivity of the PSFCo was measured as function of temperature up to 850 ℃. The sample displayed maximum electrical conductivity of 370 Scm −1 at around 550–600 ℃. The polarization behavior of PSFCo was calculated by means of AC impedance with Sm 0.8 Ce 0.2 O 2 (SDC) as electrolyte. The value of area specific resistance (ASR) was calculated as 0.146 Ωcm 2 at 800 ℃ and 0.248 Ωcm 2 at 700 ℃.

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