Efficient Preparation of Isotactic Polypropylene-Based Block Copolymers with Tunable Mechanical Properties: From Thermoplastics to Elastomers

Macromolecules, Journal Year: 2024, Volume and Issue: 57(9), P. 4208 - 4219

Published: April 20, 2024

Olefin block copolymers (OBCs), which exhibit improved mechanical and thermal properties over conventional random copolymers, are high-performance polyolefin materials with promising applications in cutting-edge fields. Herein, we reported a series of isotactic polypropylene (iPP)-based OBCs both high melting temperatures (Tms) tunable properties, prepared via coordinative chain transfer polymerization, using dimethyl(pyridylamido)hafnium/[Ph3C][B(C6F5)4]/AliBu3 catalytic system. The were composed semicrystalline iPP segment Tm > 146 °C propylene/α-olefin copolymer comonomer content up to 17 mol %. microstructure the was confirmed by gel permeation chromatography along cross-fractionation chromatography. By properly tuning length composition, these exhibited ranging from tough plastics (breaking strength reaching 26 MPa, elongation at break 1170%) ductile elastomers 14 elastic recovery 84%). synthetic strategy iPP-based this study not only provides insights for academic research on but also reveals great potential industrialization high-value-added materials.

Language: Английский

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Synthesis of Cross-Linked Polyolefin Elastomers with High Performance Yet Good Reprocessability

Industrial & Engineering Chemistry Research, Journal Year: 2025, Volume and Issue: 64(9), P. 5080 - 5086

Published: Feb. 24, 2025

The development of polymer materials with high performance and good reusability is critical to sustainability the industry. However, balance these two aspects in elastomers rubbers highly challenging. Here, we report synthesis a novel polyolefin elastomer (POE) dynamically cross-linked by an imine-linked boronic ester. It improves tensile strength at break (σ) POE 148.2%, Young's modulus (E) 92.6%, toughness (UT) 49.4%, slightly decreased elongation break. also has higher thermal resistance than pristine one presents steady storage plateau 2.8 MPa above 150 °C. Moreover, it can be reprocessed impressive recovery ratio UT 89.7% because dynamic exchanges ester imine. Dynamic mechanical analysis shows that cross-linking short characteristic relaxation time 9.6 min low apparent activation energy 65.1 kJ·mol–1. Our study on POEs provides new way for sustainable elastomers.

Language: Английский

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Bimodal and Highly Branched Polyethylenes Using Dual-Site Nickel Catalysts Supported on an Unsymmetrical BIAN-PI Compartmental Ligand Scaffold

Macromolecules, Journal Year: 2024, Volume and Issue: 57(3), P. 1087 - 1105

Published: Jan. 26, 2024

A straightforward two-step synthesis of a new family electronically distinct para-biphenylene-linked 1,2-bis(imino)acenaphthene/pyridyl-2-imine (BIAN-PI) ligands, 2′-CMeN{1-[2,6-(Ph2CH)2-4-R-C6H2N]-2-[3,3′,5,5′-iPr4-1,1′-(C6H2)2-4-N]C2C10H6}C5H4N (R = Me L1′, iPr L2′, tBu L3′, OMe L4′, OCF3 L5′, Cl L6′, F L7′, NO2 L8′), is disclosed. Their reaction with two equivalents NiBr2(DME) results in occupation the inequivalent N,N′ pockets within BIAN-PI framework to afford binuclear nickel(II) bromide complexes, [2′-CMeN{1-[2,6-(Ph2CH)2-4-R-C6H2N]-2-[3,3′,5,5′-iPr4-1,1′-(C6H2)2-4-N]C2C10H6}C5H4N]Ni2Br4 Ni21′, Ni22′, Ni23′, Ni24′, Ni25′, Ni26′, Ni27′, Ni28′). The molecular structures their aqua adducts, Ni21′(OH2)–Ni28′(OH2), emphasize not only dissimilar coordination environments but also variation steric protection imparted remotely positioned metal centers (Ni···Ni separation: 12.515–12.718 Å). In presence AlMe3 or Me2AlCl, these bimetallic nickel catalysts exhibited moderate high activities for ethylene polymerization (up 8.5 × 106 g (PE) mol–1 (Ni) h–1 Ni23′/Me2AlCl at 30 °C) affording polyethylenes distinctly bimodal distributions that contain both weight component and much lower one, relative ratios influenced by run temperature. all cases, were highly branched branching density strongly affected catalyst structure type aluminum-methyl activator employed. Moreover, showed superior tensile strength comparable elastic recovery when compared unimodal material produced using mononuclear comparator, [1-[2,6-(Ph2CH)2-4-NO2–C6H2N]-2-[4′-NH2-3,3′,5,5′-iPr4-1,1′-(C6H2)2-4-N]C2C10H6]NiBr2 (Ni8). Indeed, types materials can be considered as promising candidates use thermoplastic elastomers. addition Ni8, three other complexes (Ni9–Ni11) mimic Ni28′ have been prepared studied binary catalysts.

Language: Английский

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Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Macromolecules, Journal Year: 2024, Volume and Issue: 57(15), P. 6899 - 6913

Published: July 23, 2024

Language: Английский

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High-Performance Olefin Thermoplastic Elastomer Based on Dynamically Cross-Linking Crystalline Macromers and Elastic Backbones

Macromolecules, Journal Year: 2024, Volume and Issue: 57(4), P. 1788 - 1794

Published: Feb. 13, 2024

Developing novel olefin thermoplastic elastomers (TPE-Os) that outperform those with well-defined block or grafted chain structures is both highly attractive and challenging. Here, we report the preparation of high-performance TPE-Os in a combinatorial way. Semicrystalline ethylene/1-octene/diene copolymers pendant vinyl groups crystalline polyethylene macromers terminal double bonds are synthesized, they dynamically linked dithiol-based cross-linker containing boronic ester bond to form new TPE-O. Due synergy between physical crystallization dynamic cross-linking, it exhibits significantly increased Young's modulus (E), elongation at break (ε), ultimate strength (σ), tensile toughness (UT) up 27.2 ± 3.8 MPa, 902 28%, 26.7 1.1 120.1 9.5 MJ·m–3, respectively, which among highest levels cross-linked traditional TPE-Os. It also has good elasticity 10-cycle elastic recovery ratio 71.4%; high melting point nearly 123.8 °C σ can even maintain 0.14–0.42 MPa 200 °C. The TPE-O offers reprocessing performance 113.2% for E, 98.5% ε, 95.8% σ, 92.5% UT. We believe our study will facilitate development next-generation higher performance.

Language: Английский

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Mechanochromic Polyolefin Elastomers

ACS Applied Polymer Materials, Journal Year: 2024, Volume and Issue: 6(11), P. 6572 - 6580

Published: May 30, 2024

The optical detection of mechanical strain and stress in polymers is a powerful convenient approach for studying deformation processes these materials identifying damage prior to failure crucial components. We show here that mechanochromic behavior can be introduced via straightforward one-step process involves the modification commercial polyolefin elastomer (POE) grafted with reactive anhydride groups small amounts (<0.8 wt %) cross-linkers (Loop or sPDI). These motifs contain excimer-forming perylene diimides (PDIs) react POE afford elastomers (POE-Loop POE-sPDI). Loop motif contains two PDI moieties form folded structures which PDIs within interact each other, i.e. intra-Loop, while sPDI one only interactions other probes. Upon POE-Loop POE-sPDI, dye aggregates disassemble ratio monomer-to-excimer emission intensity increases. data suggest between probes, inter-Loop inter-sPDI, dominate characteristics both polymers.

Language: Английский

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Reactive melt‐grafting of maleic anhydride onto olefin block copolymer toward high‐performance polar polyolefin thermoplastic elastomer

Polymer International, Journal Year: 2024, Volume and Issue: 73(7), P. 545 - 555

Published: March 5, 2024

Abstract The block structure of olefin copolymer (OBC) elastomer gives it good elasticity and heat resistance relative to other polyolefin elastomers. However, the non‐polar nature OBC chains limits its comprehensive properties like dyeing toughening for polar engineering plastics. In this work, maleic anhydride (MA) dicumyl peroxide (DCP) were selected as a typical monomer radical initiator modify polarity elastomer. During melt‐grafting process, DCP content was tuned optimize grafting efficiency while MA‐to‐OBC ratio fixed at 5 wt%. It found that all reactions show high can be finished in 3 min 170 °C. With increase content, estimated degree OBC‐ g ‐MA increases from 0.40% 1.16% along with increased gel 4.27% 22.44%. A suitable process obtained 3.0 wt% by balancing final mechanical properties. optimized 0.92% has strength 17.15 MPa, Young's modulus 26.35 elongation 1564% strain recovery 59.73%. Additionally, contact angle test shows surface hydrophilicity excessive crosslinking promotes hydrophobicity. Therefore, our work demonstrated feasibility reactive method prepare also provide processing reference chemical functionalization thermoplastic © 2024 Society Industrial Chemistry.

Language: Английский

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Recent Advances in Controlled Production of Long‐Chain Branched Polyolefins

Macromolecular Rapid Communications, Journal Year: 2024, Volume and Issue: 45(12)

Published: March 16, 2024

Abstract Polyolefins, composed of carbon and hydrogen atoms, dominate global polymer production. This stems from the wide range physical mechanical properties that various polyolefins can cover. Their versatile are largely tuned by chain microstructure, including molar mass distribution, comonomer content, long‐chain branching (LCB). Specifically, LCB imparts unique characteristics, notably enhances processability crucial for downstream applications. Tailoring structural features has encouraged academic industrial efforts, chronicle in this review a chemistry standpoint. While encompassing post‐reaction modification based traditional methods like peroxide grafting, ionizing beam irradiation, coupling reactions, main focus is given to catalyst‐centric strategies innovative polymerization schemes. The advent single‐site catalysts—metallocenes late transition metals catalysts—amplifies interest tailored chemical methods, but progress formation flourishes via tandem catalytic systems bimetallic catalysts under controlled reaction conditions. breakthrough coordinative transfer unveils novel avenue synthesis sequential propagation, transfer, liberation, enchainment. short highlights recent approaches production provide roadmap researchers academia industry, steering their efforts toward further advancements polyolefin.

Language: Английский

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Synthesis of Amido-Quinoline-Based Hafnium and Zirconium Complexes and Their Catalytic Properties for Ethylene/1-Octene Copolymerization

Polymers, Journal Year: 2025, Volume and Issue: 17(4), P. 449 - 449

Published: Feb. 8, 2025

The development of polyolefin catalysts plays a pivotal role in driving advancements within the industry. In this study, five ligands (L1–L5) and six Hf (Hf 1-5) Zr (Zr-1) metal complexes with amido-quinoline-based were successfully synthesized by simple efficient synthetic route. new exhibit high thermal stability, moderate activity, excellent 1-octene incorporation capability. As result, they have been utilized high-temperature solution-phase polymerization to produce elastomers (POEs). electron-donating effect ligand was identified as crucial factor contributing improved catalytic performance comonomer steric effects substituents on little impact olefin copolymerization molecular weight, Hf-1 complex demonstrates outstanding activity (8.3 × 106 g polymer/(mol catalyst · h), 26 wt%), offering significant potential for large-scale operations practical applications.

Language: Английский

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Thermostable Polyhalogen-Substituted α-Diimine Nickel Precatalysts Towards High Performance Polyethylene Elastomer

Journal of Molecular Structure, Journal Year: 2025, Volume and Issue: 1334, P. 141892 - 141892

Published: March 1, 2025

Language: Английский

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