Polymeric Dynamic Crosslinker for Upcycling of Fragile Low-Molecular-Weight Polypropylene

ACS Applied Polymer Materials, Journal Year: 2023, Volume and Issue: 5(6), P. 4056 - 4068

Published: May 22, 2023

While tremendous progress has been made in the dynamic crosslinking of polypropylene (PP) for plastic upcycling, efficacy addressing low-molecular-weight (MW) PP waste remains untapped. In this work, we demonstrate a simple and scalable method to convert brittle low-MW vitrimer materials with enhanced thermal mechanical properties, enabling their use circular upcycling. Different from most previous work employing small-molecule crosslinkers, prepare vitrimers (PPv) using polymeric containing polyethylene glycol segments, which leads altered crystalline structures network formation. Importantly, by increasing MW crosslinkers 200 1000 Da, PPv exhibit more than 50 times increase fracture energy strong ductility, can be attributed combined effects strengthened amorphous regions semi-crystalline domains phase separation between soft segments matrix. Moreover, when blending high (PPh), PPh/PPv blends show comparable elastic modulus, yield strength, stretchability that PPh, sharp contrast widely known embrittlement PP/PPh blends. These results as an important strategy upcycling value-added products.

Language: Английский

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Novel covalent adaptable networks (CANs) of ethylene/1-octene copolymers (EOCs) made by free-radical processing: comparison of structure–property relationships of EOC CANs with EOC thermosets

Polymer Chemistry, Journal Year: 2023, Volume and Issue: 14(31), P. 3621 - 3637

Published: Jan. 1, 2023

Various ethylene/1-octene copolymers were upcycled into reprocessable covalent adaptable networks to study structure–property relationships relative their thermoset counterparts.

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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Mechanically Ultra‐Robust Fluorescent Elastomer for Elaborating Auxetic Composite

Small, Journal Year: 2024, Volume and Issue: unknown

Published: April 28, 2024

Fluorescent elastomers are predominantly fabricated through doping fluorescent components or conjugating chromophores into polymer networks, which often involves detrimental effects on mechanical performance and also makes large-scale production difficult. Inspired by the heteroatom-rich microphase separation structures assisted intensive hydrogen bonds in natural organisms, an ultra-robust polyurethane elastomer is reported, features a remarkable fracture strength of 87.2 MPa with elongation 1797%, exceptional toughness 678.4 MJ m

Language: Английский

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Multifunctional Waterborne Polyurethane with Robustness, Adhesiveness, and Self-Healability Based on a Dual Cross-Linked Network Containing Multiple Dynamic Bonds

ACS Applied Polymer Materials, Journal Year: 2024, Volume and Issue: 6(21), P. 13389 - 13400

Published: Oct. 24, 2024

Waterborne polyurethane with a combination of high strength, toughness, and self-healing efficiency is attractive in many fields, but the development such materials remains challenging due to contradictions these properties. In this work, cross-linked waterborne (DWPU) was successfully prepared by introducing cross-linking agent containing reversible disulfide acylhydrazone bonds on linear backbone. The dual network covalent hydrogen bonding improves stability provides excellent mechanical properties for elastomers, while synergistic action dynamic bonds, imparts outstanding performance. As result, DWPU exhibits tensile strength (49.34 MPa), exceptional Young's modulus (305.4 satisfactory toughness (214.8 MJ m–3), rapid (over 90%). Thanks abundant polar groups, presents tough adhesion various substrates, as aluminum, glass fiber, epoxy resin. addition, it has good transparency inherent blue fluorescence. By integration ability fluorescence properties, process could be traced detecting change intensity crack positions. This study not only simple way preparation high-performance multifunctional environmentally friendly polymers also broadens their application fields optical anti-counterfeiting, protective coatings, smart devices, so on.

Language: Английский

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Biomimetic Nanostructured Polyimine Aerogels with Graded Porosity, Flame Resistance, Intrinsic Superhydrophobicity, and Closed-Loop Recovery

ACS Nano, Journal Year: 2024, Volume and Issue: 18(52), P. 35465 - 35479

Published: Dec. 16, 2024

Polymer aerogels, with their porous and lightweight features, excel in applications such as energy storage, absorption, thermal insulation, making them a sought-after new material. However, the covalent cross-linking networks of current polymer aerogels result unsustainable manufacturing processing practices, persistently depleting our finite natural resources causing significant global environmental impacts. Herein, we have constructed high-performance dynamic aerogel network using biobased materials, its structure green sustainability akin to those plants nature. Abundant reversible points endow ultrafast degradation capabilities, enabling allow for closed-loop chemical monomer recovery reprocessing. Furthermore, utilizing highly active network, net-zero emission material reuse reprocessing can be achieved. Additionally, controlled features multilevel roughness nanostructured surface similar lotus leaf biomimetic pore structure, contributing anisotropy. The distinctive composition high compressive strength (2.2 MPa) vertically, low conductivity (0.0257 W/(m·K)) horizontally, outstanding fire resistance (LOI is 36%). Notably, demonstrates highest hydrophobicity among polyimine contact angle 154°. excellent performance variety potential oil–water separation, directional transport, phase change it anticipated that these will greatly benefit from systematic upgrades recyclability

Language: Английский

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Molecularly Defined Polyolefin Vitrimers from Catalytic Insertion Polymerization

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(29), P. 13226 - 13233

Published: July 15, 2022

Vitrimers can combine the advantageous properties of cross-linked materials with thermoplastic processability. For prominent case polyethylene, established post-polymerization introduction cross-linkable moieties results in extremely heterogeneous compositions chains. Here, we report generation functionalized polyethylenes directly by catalytic insertion polymerization, incorporated aryl boronic esters or alternatively acetal-protected groups suited for cross-linking difunctional esters. In addition to desired homogeneous in-chain distribution, reactive are enriched at chain ends. This enables incorporation all chains network, as also supported simulations chains' compositions. The uniform molecular composition reflects resulting vitrimers' material properties, particularly lack leaching solvents. At same time, is indeed fully reversible and vitrimers be recycled.

Language: Английский

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Microstructure, Viscoelasticity, and Extensional Rheology of Ethylene–Propylene Copolymer Vitrimers

Macromolecules, Journal Year: 2024, Volume and Issue: 57(6), P. 2729 - 2745

Published: March 14, 2024

Vitrimers of ethylene–propylene (EP) copolymers were synthesized by postreactor melt reactions with a dynamic covalent cross-linker (diacrylate bis(dioxoborolane), DBDA) and dicumyl peroxide (DCP). A novel two-step synthetic route to prepare DBDA is presented. The EP vitrimer melts show the expected chain relaxation delay due network formation. This manifests as significant increase in elasticity, viscosity, extensional strain hardening. However, it was found that degree depends not only on amount added but also comonomer ratio (E/P) copolymer precursor. E/P determines cure kinetics well-known side (i.e., beta scission, branching, cross-linking) induced DCP copolymers. AFM SAXS studies reveal formation spherical nanodomains during curing. nonoccurrence macrophase separation cured vitrimers led us postulate are made clustered poly(DBDA) chains grafted onto backbones. complex topology, resulting from DCP-induced combined nanoclusters, possibly acting nanofillers, has strong effect structure–rheology correlations.

Language: Английский

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Preparation of Styrene–Butadiene Rubber Vitrimers with High Strength and Toughness through Imine and Hydrogen Bonds

Industrial & Engineering Chemistry Research, Journal Year: 2022, Volume and Issue: 62(5), P. 2299 - 2308

Published: Oct. 31, 2022

The covalent cross-linked structure imparts strong elasticity and environmental resistance to elastomers, while the irreversibility of bonds restricts recycling rubbers. Integrating vitrimer chemistry into chemical networks appears be a charming method combine exciting properties thermoplastics thermosets. However, it is still challenge design rubber with robust mechanical properties. Here, inspired by supramolecular interactions associated natural materials, we demonstrated dual reversible SBR introducing imine hydrogen bonding. integration bonding endows elastomer significantly improved strength toughness without influencing ability. This work provides simple effective strategy in vitrimers good recyclability.

Language: Английский

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Facile Approach for the Preparation of Robust and Thermally Stable Silyl Ether Cross-Linked Poly(ethylene-vinyl acetate) Vitrimers

ACS Applied Polymer Materials, Journal Year: 2023, Volume and Issue: 5(10), P. 8379 - 8386

Published: Sept. 11, 2023

Vitrimers as an emerging class of dynamic polymer networks hold great promise for the development sustainable thermosets. While straightforward method to prepare vitrimers from commodity polymers is cost-competitive, most studies involved synthesis with specific functional groups and/or crosslinkers. Herein, we demonstrated a simple and scalable approach produce poly(ethylene-vinyl acetate) (EVA) by direct cross-linking industrial EVA product commercial bis[3-(trimethoxysilyl)propyl]amine using titanium(IV) butoxide catalyst through reactive blending. Incorporation thermally stable silyl ether cross-links into network led significantly enhanced thermal mechanical properties. Compared original EVA, resulting showed up 4 2 times improvement in Young's modulus tensile strength, respectively. The creep resistance vitrimer increased density, notably, EVA-V0.8 displayed low permanent deformation 1.2% at high temperature 180 °C, much higher than normal service temperature. Moreover, excellent reprocessability recyclability, modulus, elongation break were nearly identical even after four recycling.

Language: Английский

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