Polypropylene Covalent Adaptable Networks with Full Cross-Link Density Recovery after Reprocessing: Development by Free-Radical Reactive Processing with Resonance-Stabilized, Aromatic Disulfide Cross-Linkers

ACS Macro Letters, Journal Year: 2025, Volume and Issue: unknown, P. 341 - 348

Published: March 5, 2025

A single-step method that produces percolated, dynamic covalent cross-links integrated into the PP homopolymer has not been previously demonstrated. Here, we synthesized adaptable networks (CANs) from polypropylene (PP) homopolymers using 180 °C, radical-based, reactive processing with a free-radical initiator, dicumyl peroxide (DCP), and resonance-stabilized, aromatic disulfide cross-linkers, one methacrylate-based another phenyl acrylate-based. Both cross-linkers yielded when reactively processed at 4 wt % relatively high molecular weight (MW) (melt flow index (MFI) = 12) DCP. The acrylate-based cross-linker also other studied DCP/cross-linker concentrations low MW (MFI 35). Notably, our highest cross-link density CAN exhibited full recovery of after three reprocessing steps by compression molding; within experimental uncertainty melt extrusion.

Language: Английский

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Reactive Processing of Polyethylene with Azidotriazine: From Modified Thermoplastics to Injection Moldable Covalent Adaptable Networks

ACS Applied Polymer Materials, Journal Year: 2025, Volume and Issue: 7(3), P. 2123 - 2133

Published: Jan. 31, 2025

The increasing consumption of polyethylene (PE) is an important concern for society because the rate PE recycling remains low compared to scale production. There thus great interest in strategies revalorizing waste. In this context, our group recently reported approach transforming into nanostructured covalent adaptable networks (CANs) with azidotriazine grafting agents using reactive extrusion. These CANs feature polyazane cross-links that undergo thermomechanically activated exchange reactions, permitting material flow when subjected high temperature and strain. Herein, we exploited chemistry develop modified materials intriguing thermomechanical properties exceptional processability. A family compositions was prepared by reactively extruding varying amounts agent, resulting were studied a combination electron microscopy, small-angle X-ray scattering, calorimetry, rheometry, mechanical testing. As loading agent increased from 0.05 1.0 mol %, transitioned being thermoplastic-like thermoset-like, revealing balance properties, melt strength, high-temperature creep resistance. Surprisingly, all samples─even loadings azidotriazine─could be easily shaped injection molding. We believe promising, industrially relevant way enhance polyolefins.

Language: Английский

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Fluorescent Nanoporous Materials from Polypropylene-Based Covalent Adaptable Networks

ACS Omega, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Fluorescent polypropylene-based aerogels from thermoreversibly crosslinked networks have been developed. This facile and efficient synthesis results in low-cost, recyclable, chemically resistant, highly porous functional materials. process includes the chemical crosslinking of polypropylene, followed by thermal phase separation freeze-drying, yielding with specific surface areas up to 200 m2/g, according nitrogen absorption-desorption measurements. is significantly higher than that previously reported for polypropylene Besides characterizations polymer infrared spectroscopy differential scanning calorimetry, a suite analytical techniques was utilized characterize skeletal framework aerogels, including electron microscopy small-angle X-ray scattering. These methods revealed nanostructural features interconnected 3D networks. The modulation excited-state properties incorporated luminophore demonstrated provides insights into their potential applications. Importantly, pronounced ability retain toluene, affecting fluorescence behavior over an extended time scale. conceptual study presents low-cost solution preparation materials might offer versatility functionality may open door further exploration design high-performance can act very effectively sensing adsorption organic molecules. also provide intriguing direction future research focusing on molecular mechanisms driving observed modulations.

Language: Английский

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Recycling reinvented: Converting PET bottle waste into 3D printable PCR polypropylene vitrimers for a sustainable future

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 162432 - 162432

Published: April 1, 2025

Language: Английский

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Reprocessable Polypropylene Covalent Adaptable Networks via Free-Radical Reactive Processing with Vinyl Aromatic Additives

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: April 23, 2025

Language: Английский

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Design and Continuous (Re)Processing of Thermally Resilient Poly(Styrene-co-Maleic Maleate)-Based Covalent Adaptable Networks

Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(15), P. 7487 - 7503

Published: Aug. 5, 2024

Cyclic anhydrides, classical monomers for bulk synthetic materials, have recently gained attention in covalent adaptable networks (CANs). They undergo reversible ring-opening with polyols, forming dynamic monoester linkages. This inherent property makes cyclic anhydrides ideal industrially relevant polymer matrices CAN-like recycling and reprocessing capabilities. Our study presents a rational design poly(styrene-co-maleic maleate) (PS-MME)-based networks, achieved by cross-linking commercially available anhydride) (PS-co-MA) series of diols. The network synthesis is not only feasible on large scale under solvent-free conditions but also allows the tailoring final degree properties independently tuning PS-co-MA maleic anhydride content, its chain length, and/or loading cross-linker diols used. Previous limitations thermal stability MME-based CANs, stemming from remaining free carboxyl acids linkages, are circumvented through dilution reactive sites an apolar matrix switching to ring embedded into backbone. robust macromolecular architecture enhances kinetics thermodynamics formation, resulting PS-MMEs exceptional resilience. Even at temperatures exceeding 210 °C, exhibit fast cross-link exchange without compromising their rheological, mechanical, or properties. feature enables continuous (re)processing via extrusion injection molding solvent-assisted recovery pure starting polyol linear polymers, facilitating chemical use new materials. In other words, this research paves way applicable CANs leveraging widely used polymers.

Language: Английский

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Effect of annealing treatment on impact toughness and crystallization behaviors of polypropylene/ethylene vinyl acetate copolymer/layered double hydroxide composites

Polymer Composites, Journal Year: 2024, Volume and Issue: 45(17), P. 16193 - 16204

Published: Aug. 15, 2024

Abstract This research endeavors to explore the potential of annealing treatment as a viable strategy optimize utilization polypropylene (PP) composites, while preserving their exceptional properties. By incorporating ethylene vinyl acetate (EVA) copolymer and layered double hydroxide (LDH) into PP, this work meticulously analyzes changes in crystallization behaviors impact properties under varying conditions. Impact strength is systematically assessed by digital pendulum tester, whereas crystalline structure analyzed through polarized light optical microscopy (POM), differential scanning calorimetry (DSC), x‐ray diffraction (XRD). The notch test exhibits gradual increase from 100 130°C, followed decline at 140°C. XRD DSC results elucidate subtle β‐crystal peaks for PP/EVA PP/EVA/LDH attributed transformative effect EVA LDH on PP crystals. POM analysis further unveils reduction spherical crystal size blurring grain boundaries during process. Highlights composites are effectively regulated changing induced due synergistic treatment. toughness enhanced significantly

Language: Английский

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A Study on the Impact of Chemical Structure on the Evolution of Aggregate Structure in Fiber-shaped High Density Polyethylene Vitrimer

Chinese Journal of Polymer Science, Journal Year: 2024, Volume and Issue: 42(10), P. 1557 - 1565

Published: Aug. 21, 2024

Language: Английский

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Dual dynamic lignin-based covalent adaptable networks: Multiple recyclability and photothermal healing capabilities

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: unknown, P. 158652 - 158652

Published: Dec. 1, 2024

Language: Английский

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The conformational preference of dynamic crosslinker modulates the ‘closed-loop’ circular economy in polypropylene vitrimer

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: unknown, P. 158696 - 158696

Published: Dec. 1, 2024

Language: Английский

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