Ring-opening Metathesis Polymerization Research Articles

Chemically recyclable rosin-based polymers

The pursuit of next-generation sustainable polymers with chemical recyclability and resource renewability has become a priority in materials science. Rosin, a widely available renewable natural biomass, holds promise in this regard. In this study, dehydroabietic acid was incorporated into a cyclooctene monomer structure as pendant groups. This tailored monomer with low ring strain possesses the ability to efficiently undergo ring-opening metathesis polymerization (ROMP), resulting in the synthesis of rosin-based unsaturated polymers with a fully hydrocarbon backbone. The molecular weight of these polymers, ranging from 50 kDa to 160 kDa, can be easily modulated by varying the monomer-to-catalyst feeding ratio. Remarkably, these amorphous polymers exhibit exceptional thermostability, with a decomposition temperature exceeding 400 °C. This type of polymer exhibits excellent acid and alkali resistance within a pH range of 3 to 11. Upon exposure to Grubbs II catalyst under mild conditions, these polymers undergo depolymerization back to the native monomer in a highly efficient manner, achieving a remarkable recovery ratio of approximately 95 %. It is evident that this innovative approach is not only relevant for the development of rosin-based polymers but also holds promise for informing the design of other renewable polymers with superior thermostability and enhanced chemical recyclability.

Highly sensitive electrochemical quantification of carbendazim via synergistic enhancement of ring-opening metathesis polymerization and polyethyleneimine modified graphene oxide.

Anovel aptamer-based sensor was developed using the signal amplification strategy of ring-opening metathesis polymerization (ROMP) and polyethyleneimine modified graphene oxide to achieve trace detection of carbendazim (CBZ). The dual identification of aptamer and antibody was used to avoid false positive results and improve the selectivity. Polyethyleneimine modified graphene oxide (GO-PEI), as a substrate material with excellent conductivity, was modified on the surface of aglassy carbon electrode (GCE) to increase the grafting amount of aptamer on the electrode surface. Moreover, a large number of cyclopentenyl ferrocene (CFc) was aggregated to form long polymer chains through ring-opening metathesis polymerization (ROMP), so as to significantly improve the detection sensitivity of the biosensor. The linear range of this sensor was 1 pg/mL-100 ng/mL with a detection limit as low as 7.80fg/mL. The sensorexhibited excellent reproducibility and stability, and also achieved satisfactory results in actual sample detection. The design principle of such a sensor could provide innovative ideas for sensors in the detection of other types of targets.

Well-Tailored Norbornene-Based Fluorinated Copolymers toward Modulating Icephobicity and Mechanical Robustness.

Well-tailored construction of icephobic surfaces with mechanical robustness and investigation of the structure-property relationships at the molecular level are highly desirable. Herein, a series of norbornene-based fluorinated polyolefin copolymers (FPOR-x) with varying norbornenyl dodecafluoroheptyl ester (NDFHE) molar fractions (0-100 mol %) were well-designed and fabricated via living ring-opening metathesis polymerization (ROMP) employing NDFHE and norbornenyl pentafluorophenyl ester (NPFPE) as the soft and hard segments, respectively. The mechanical and icephobic properties of the fluorinated copolymers can be regulated by adjusting the soft NDFHE contents. As a result, the well-designed norbornene-based copolymers exhibited a wide range of tunable mechanical properties, including tensile strength ranging from 0.2 to 26.4 MPa, elastic modulus ranging from 0.6 to 593.7 MPa, and breaking elongations ranging from 5718.7% to 3.7%, correlating with the proportion of soft NDFHE content. Furthermore, the synergistic interplay between soft and hard segments, particularly the hardness in the majority and softness in the minority or vice versa, could achieve a significant difference in the local modulus and enhance the propagations of cracks within the three-phase regions (soft regions/hard regions/ice), ultimately leading to a significant reduction in ice shear strength. Notably, FPOR-25% with a tensile strength of 12.0 MPa and an elastic modulus of 227.5 MPa exhibited a remarkably low ice shear strength of 57.7 kPa. This study not only highlights the relationship between the polymer molecular structure and surface icephobic properties but also breaks the limitations of icephobic surfaces with a low modulus.

Tailoring the Structure-Property Relationship of Ring-Opened Metathesis Copolymers for CO2-Selective Membranes.

In this work, we explore the use of ring-opening metathesis polymerization (ROMP) facilitated by a second-generation Grubbs catalyst (G2) for the development of advanced polymer membranes aimed at CO2 separation. By employing a novel copolymer blend incorporating 4,4'-oxidianiline (ODA), 1,6-hexanediamine (HDA), 1-adamantylamine (AA), and 3,6,9-trioxaundecylamine (TA), along with a CO2-selective poly(ethylene glycol)/poly(propylene glycol) copolymer (Jeffamine2003) and polydimethylsiloxane (PDMS) units, we have synthesized membranes under ambient conditions with exceptional CO2 separation capabilities. The strategic inclusion of PDMS, up to a 20% composition within the PEG/PPG matrix, has resulted in copolymer membranes that not only surpass the 2008 upper limit for CO2/N2 separation but also meet the commercial targets for CO2/H2 separation. Comprehensive analysis reveals that these membranes adhere to the mixing rule and exhibit percolation behavior across the entire range of compositions (0-100%), maintaining robust antiplasticization performance even under pressures up to 20 atm. Our findings underscore the potential of ROMP in creating precisely engineered membranes for efficient CO2 separation, paving the way for their application in large-scale environmental and industrial processes.

Supersoft Norbornene-Based Thermoplastic Elastomers with High Strength and Upper Service Temperature.

With over 6 million tons produced annually, thermoplastic elastomers (TPEs) have become ubiquitous in modern society, due to their unique combination of elasticity, toughness, and reprocessability. Nevertheless, industrial TPEs display a tradeoff between softness and strength, along with low upper service temperatures, typically ≤100°C. This limits their utility, such as in bio-interfacial applications where supersoft deformation is required in tandem with strength, in addition to applications that require thermal stability (e.g., encapsulation of electronics, seals/joints for aeronautics, protective clothing for firefighting, and biomedical devices that can be subjected to steam sterilization). Thus, combining softness, strength, and high thermal resistance into a single versatile TPE has remained an unmet opportunity. Through de novo design and synthesis of novel norbornene-based ABA triblock copolymers, we fill this gap. Ring-opening metathesis polymerization (ROMP) is employed to prepare TPEs with an unprecedented combination of properties, including skin-like moduli (<100kPa), strength competitive with commercial TPEs (>5MPa), and upper service temperatures akin to high-performance plastics (∼260°C). Furthermore, the materials are elastic, tough, reprocessable, and shelf stable (≥2 months) without incorporation of plasticizer. Structure-property relationships identified herein inform development of next-generation TPEs that are both biologically soft yet thermomechanically durable. This article is protected by copyright. All rights reserved.

Improved interfacial adhesion of carbon fiber‐reinforced polydicyclopentadiene layered composite material by modification of norbornene derivatives

AbstractSurface chemical grafting modifications of carbon fibers (CFs) using 5‐(triethoxysilyl)norbornene (TOS), norbornene carboxylic acid tert‐butyl ester (NB‐TBE), and 5‐norbornene‐2,3‐dicarboxylic anhydride (NA) improved interfacial interactions between CFs and poly(dicyclopentadiene) (PDCPD) resin. The ring‐opening metathesis polymerization (ROMP) of DCPD, catalyzed by Grubbs catalyst II, enabled the fabrication of PDCPD/CF layered composite materials with resin and fibers tightly adhered. The optimal composite exhibited remarkable mechanical properties, with a tensile strength of 654.6 MPa and flexural strength of 510.7 MPa. Excellent thermal stability with a maximum weight loss rate in temperatures above 450°C and good chemical resistance with a weight change of about 1% in both acidic and alkaline media highlight the promising potential of these materials for use in harsh environments. The simple yet efficient approach of TOS, NB‐TBE, and NA‐enhanced layered CF shows great promise as advanced composite materials for industrial applications.Highlights Norbornene derivatives such as TOS, NB‐TBE, and NA are suitable modifiers for CF. ROMP of DCPD and norbornene group onto CFs, fabrication of PDCPD/CF composite materials. The composite exhibited remarkable interfacial adhesion and mechanical properties.

Reprocessability in Engineering Thermosets Achieved Through Frontal RingOpening Metathesis Polymerization.

While valued for their durability and exceptional performance, crosslinked thermosets are challenging to recycle and reuse. Here, inherent reprocessability in industrially relevant polyolefin thermosetsis unveiled. Unlike prior methods, this approach eliminates the need to introduce exchangeable functionality to regenerate the material, relying instead on preserving the activity of the metathesis catalyst employed in the curing reaction. Frontal ring-opening metathesis polymerization (FROMP) proves critical to preserving this activity. Conditions controlling catalytic viability are explored to successfully reclaim performance across multiple generations of material, thus demonstrating long-term reprocessability. This straightforward and scalable remolding strategy is poised for widespread adoption. Given the anticipated growth in polyolefin thermosets, these findings represent an important conceptual advance in the pursuit of a fully circular lifecycle for thermoset polymers.

The effect of polymer with tunable alkyl spacers on the microstructure of amphoteric membrane for vanadium redox flow battery (VRB)

Amphoteric membranes, as promising candidates for VRBs, have attracted more attention. The side-chain-type polymers go far towards improving ion exchange capacity and further enhancing ion conductivity. A kind of Amphoteric ion exchange membranes (AIEMs) with different alkyl chain lengths (C2, C6, and C12 spacers) were synthesized by using ring-opening metathesis polymerization (ROMP). In addition, the interactions between N-containing groups with positively charged and -SO3- groups prevent swelling and vanadium crossover. The microphase separation structure through side chain induction was regulated, to respond to the ionic mobility of the membrane. The effect of the spacer lengths on the ion selectivity of AIEMs is investigated. In addition, the size and matrix of the constructed ion channel were calculated by using coarse-grained molecular dynamics (CGMD) simulation, which further verified the experiment.

Remarkable impact of chain backbone on the performance of Poly(norbornene derivatives)-based anion exchange membranes

Chemical stability and the trade-off between ion conductivity and dimensional stability are two primary challenges for the development of suitable anion exchange membranes (AEMs). Herein, a series of non-crosslinked poly(norbornene derivatives)-based AEMs containing a bulky steric hindrance hydrophobic arylene substituent were prepared by vinyl addition polymerization (VAP), ring-opening metathesis polymerization (ROMP), and ROMP followed post-hydrogenation, respectively. Compared with ROMP and hydrogenated type membranes, VAP-type membranes, especially the VAP-N-50, exhibited excellent dimensional stability with limited swelling ratio (SR = 27.9 %) while higher water uptake (WU = 213.8 %) at 80 °C, which is attributed to its rigid VAP-type cyclic chain backbone. Microtopography study demonstrated the existence of nanoscale phase separation in VAP-type AEMs and its association with water uptake and swelling behavior. VAP-N-60 showed excellent hydroxide conductivity up to 105.5 mS cm−1 at 80 °C, while exhibited superior alkaline stability that was not found in ROMP-type membrane ROMP-N-50 and the hydrogenated-type membrane H-ROMP-N-50. After being immersed in 2 M NaOH solution at 80 °C for 1200 h, the hydroxide conductivity loss of VAP-N-60 was only 3.0 %. Furthermore, a H2/O2 single cell using VAP-N-50 membrane achieved the highest peak power density of 722 mW cm−2 at 60 °C without back pressure.

A high-performance liquid Ru-based metathesis catalyst for the ring-opening metathesis polymerization of dicyclopentadiene

A high-performance liquid Ru-based metathesis catalyst for the ring-opening metathesis polymerization of dicyclopentadiene

Upgrading of thermosets and composites via sequential frontal ring-opening metathesis polymerization and radical reactions

Upgrading of thermosets and composites via sequential frontal ring-opening metathesis polymerization and radical reactions

Polyheptenamer: A chemically recyclable polyolefin enabled by the low strain of seven‐membered cycloheptene

AbstractLow‐strain cyclic olefin monomers, including five‐membered, six‐membered, eight‐membered, and macrocyclic rings, have been recently exploited for the synthesis of depolymerizable polyolefins via ring‐opening metathesis polymerization (ROMP). Such polyolefins can undergo ring‐closing metathesis depolymerization (RCMD) to regenerate their original monomers. Nevertheless, the depolymerization behavior of polyolefins prepared by ROMP of seven‐membered cyclic olefins, an important class of low‐strain rings, still remains unexplored. In this study, we demonstrate the chemical recycling of polyheptenamers to cycloheptene under standard RCMD conditions. Highly efficient depolymerization of polyheptenamer was enabled by Grubbs' second‐generation catalyst in toluene. It was observed that the monomer yields increased when the depolymerization temperature increased and the starting polymer concentration was reduced. A near‐quantitative monomer regeneration (&gt;96%) was achieved within 1 h under dilute conditions (20 mM of olefins) at 60°C. Moreover, polyheptenamer exhibited a decomposition temperature above 430°C, highlighting its potential as a new class of thermally stable and chemically recyclable polymer materials.

Ring‐opening metathesis polymerization for synthesizing molecular bottlebrushes via the grafting‐through strategy

AbstractMolecular bottlebrush (MBB) has been considered as an important type of unimolecular nanomaterial for widespread applications ranging from energy to biomedicine, due to its typical one‐dimensional molecular conformation with tunable aspect ratio and chemical composition. In the recently decades, the ring‐opening metathesis polymerization (ROMP) combined with the grafting‐through strategy has emerged as a powerful tool for synthesizing MBBs with various architecture, including (multi)block MBBs, core‐shell MBBs, random MBBs and Janus MBBs et al. In this review, the recent advances on the synthesis of MBBs including the rational preparation of NB terminated macromonomers (MMs) and the grafting‐through ROMP are briefly summarized. Moreover, the emerging progress on the grafting‐through ROMP performed in the aqueous media is also highlighted.

Chemically Recyclable, High Molar Mass Polyoxazolidinones via Ring-Opening Metathesis Polymerization.

The development of robust methods for the synthesis of chemically recyclable polymers with tunable properties is necessary for the design of next-generation materials. Polyoxazolidinones (POxa), polymers with five-membered urethanes in their backbones, are an attractive target because they are strongly polar and have high thermal stability, but existing step-growth syntheses limit molar masses and methods to chemically recycle POxa to monomer are rare. Herein, we report the synthesis of high molar mass POxa via ring-opening metathesis polymerization of oxazolidinone-fused cyclooctenes. These novel polymers show <5% mass loss up to 382-411 °C and have tunable glass transition temperatures (14-48 °C) controlled by the side chain structure. We demonstrate facile chemical recycling to monomer and repolymerization despite moderately high monomer ring-strain energies, which we hypothesize are facilitated by the conformational restriction introduced by the fused oxazolidinone ring. This method represents the first chain growth synthesis of POxa and provides a versatile platform for the study and application of this emerging subclass of polyurethanes.

Amphiphilic Dendronized Copolymer-Encapsulated Au, Ag and Pd Nanoparticles for Catalysis in the 4-Nitrophenol Reduction and Suzuki-Miyaura Reactions.

The branched structures of dendronized polymers can provide good steric stabilization for metal nanoparticle catalysts. In this work, an amphiphilic dendronized copolymer containing hydrophilic branched triethylene glycol moieties and hydrophobic branched ferrocenyl moieties is designed and prepared by one-pot ring-opening metathesis polymerization, and is used as the stabilizer for metal (Au, Ag and Pd) nanoparticles. These metal nanoparticles (Au nanoparticles: 3.5 ± 3.0 nm; Ag nanoparticles: 7.2 ± 4.0 nm; Pd nanoparticles: 2.5 ± 1.0 nm) are found to be highly active in both the 4-nitrophenol reduction and Suzuki-Miyaura reactions. In the 4-nitrophenol reduction, Pd nanoparticles have the highest catalytic ability (TOF: 2060 h-1). In addition, Pd nanoparticles are also an efficient catalyst for Suzuki-Miyaura reactions (TOF: 1980 h-1) and possess good applicability for diverse substrates. The amphiphilic dendronized copolymer will open a new door for the development of efficient metal nanoparticle catalysts.

PhotoROMP: The Future Is Bright.

Since the earliest investigations of olefin metathesis catalysis, light has been the choice for controlling the catalyst activity on demand. From the perspective of energy efficiency, temporal and spatial control, and selectivity, photochemistry is not only an attractive alternative to traditional thermal manufacturing techniques but also arguably a superior manifold for advanced applications like additive manufacturing (AM). In the last three decades, pioneering work in the field of ring-opening metathesis polymerization (ROMP) has broadened the scope of material properties achievable through AM, particularly using light as both an activating and deactivating stimulus. In this Perspective, we explore trends in photocontrolled ROMP systems with an emphasis on approaches to photoinduced activation and deactivation of metathesis catalysts. Recent work has yielded a myriad of commercial and synthetically accessible photosensitive catalyst systems, although comparatively little attention has been paid to achieving precise control over polymer morphology using light. Metal-free, photophysical, and living ROMP systems have also been relatively underexplored. To take fuller advantage of both the thermomechanical properties of ROMP polymers and the operational simplicity of photocontrol, clear directions for the field are to improve the reversibility of activation and deactivation strategies as well as to further develop photocontrolled approaches to tuning cross-link density and polymer tacticity.

From monomer to polymer: Controlled synthesis and comprehensive analysis of poly(p-phenylene vinylene) via ROMP

This study focuses on synthesis and evaluation of [2.2] paracyclophane-1,9-diene to produce a soluble poly(p-phenylenevinylene) (PPV) derivative homopolymer using ring-opening metathesis polymerization (ROMP). The resulting homopolymer displayed a narrow polydispersity index (PDI) of 1.22, indicating precise control over polymerization. The PPV derivative exhibited excellent solubility in various organic solvents. Photophysical properties, including optical absorption and fluorescence emission spectra, were investigated to evaluate utilization in optoelectronic devices. Optical band gaps ranged from 2.21 to 2.25 eV for thin films and 2.07 to 2.19 eV for solutions, while the electrochemical band gap, determined by cyclic voltammetry, was 2.37 eV. These materials demonstrated promising fluorescence activity in various solvents and thin films, suggesting potential applications in organic light-emitting diodes (OLEDs) and related optoelectronic devices.

Approaching Tryptophan-Derived Polynorbornene Fluorescent Chemosensors: Synthesis, Characterization, and Sensing Ability for Biomedical Applications as Biomarkers for Detecting Fe2+ Ions.

We present a novel group of tryptophan (Trp)-based fluorescent polymeric probes synthesized via ring-opening metathesis polymerization (ROMP) of Trp-derived norbornene monomers. These probes, in mono- and disubstituted forms, incorporate amide and ester anchoring groups. The quantity of Trp substituents did not affect fluorescence selectivity but influenced quenching percentage. Poly-diamide-Trp, Poly-monoamide-Trp, Poly-diester-Trp, and Poly-monoester-Trp probes displayed selective detection of Fe2+ and Fe3+ ions with fluorescence on-off characteristics. Poly-diamide-Trp and Poly-monoamide-Trp exhibited a limit of detection (LOD) for Fe2+ and Fe3+ ions of 0.86-11.32 μM, while Poly-diester-Trp and Poly-monoester-Trp showed higher LODs (21.8-108.7 μM). These probes exhibited high selectivity over Fe2+, a crucial metal ion in the body known for its redox properties causing oxidative stress and cell damage. Cell cytotoxicity tests in various cell types confirmed biocompatibility. Additionally, Poly-diamide-Trp displayed excellent cell permeability and iron ion detection in EA.hy926 cells, suggesting potential for bioimaging and clinical applications.

Simultaneous Spin Coating and Ring-Opening Metathesis Polymerization for the Rapid Synthesis of Polymer Films.

We report a highly controlled technique for the synthesis of polymer films atop a substrate by combining spin coating with ring-opening metathesis polymerization (ROMP), herein termed spin coating ROMP (scROMP). The scROMP approach combines polymer synthesis and deposition into one process, fabricating films of up to 36 cm2 in under 3 min with orders-of-magnitude reduction in solvent usage. This method can convert numerous norbornene-type molecules into homopolymers and random copolymers as uniform films on both porous and nonporous substrates. Film thickness can be varied from a few hundred nanometers to a few tens of micrometers based on spin speed and monomer concentration. The resulting polymers possess high MW (>100 kDa) and low polydispersity (PDI) (<1.2) values that are similar to ROMP polymers made in solution. We also devise a model to investigate the balance between convective monomer spin-off and polymer growth from the surface, which allows the determination of critical kinetic parameters for scROMP. Finally, translation of scROMP to porous supports enables the synthesis of thin film composite membranes that demonstrate the ability to dehydrate ethanol by pervaporation.

Abstract 481: Proteomimetic polymers limit tumor growth in multiple models via potent antigen-specific T cell activation

Abstract Background: Patient-specific cancer vaccines derived from tumor antigen have been explored as a promising therapeutic strategy, however, challenges delivering vaccine components in a coordinated fashion to elicit antitumor responses remain. To overcome these, we utilize a novel nanoplatform called the Protein-Like Polymer (PLP), which allows for sustained and targeted delivery of tumor antigens in conjunction with adjuvants. Methods: PLPs containing peptide antigens were synthesized via ring-opening metathesis polymerization (ROMP) and characterized. A library of compounds with different sidechain linkage chemistries, degrees of polymerization (DP), and inclusion/exclusion of Oligo-ethylene glycol (OEG) were made to determine design rules for immune activation. Cell uptake and functional assays using payload-specific T Cells were conducted. Immunization in three independent tumor models was done to show generalizability. Ability of PLPs to co-deliver adjuvants was tested by electrostatically coupling small molecule STING agonist, 2’3’ cGAMP. Results: Conjugating peptide antigens to the polymer via a cleavable disulfide linkage, which reduces intracellularly in APCs, resulted in increased endosomal localization, higher levels of induced T cell proliferation, cytokine production, and expression of activation markers in CTLs and APCs. Incorporating a diluent amount of OEG side chains reduced enzymatic degradation while increasing immunogenicity and uptake. Additionally, increasing the DP, and therefore the density of antigen side chains, further improved vaccine efficacy and resistance to proteolysis. Antigen-PLP conjugates enhanced dendritic cell activation and T-cell response only when paired with cells from their cognate system, with no activity in immune cells not expressing receptors for the payload demonstrating antigen-specificity. Mice bearing established B16F10, MC38, or TC-1 tumors treated with PLPs containing gp100, adpgk, or E7 respectively all showed increased survival times, reduced tumor burden with corresponding changes in immune cell profiles, and immunological memory upon rechallenge. Impressively, mice treated with STING-PLP complexes had significantly smaller tumors vs control at day 14 (0.038g vs 0.76g; p &amp;lt;0.0001) and allowed for subcutaneous administration of 2’3’ cGAMP, which traditionally requires intratumoral injection. Studies on the effects of vaccinating with pools of neoantigens multiplexed onto one PLP are ongoing. Conclusion: This work validates the ability of PLPs to overcome major limitations in cancer vaccine development. The modularity of the platform allows for complex nano-architectures including systems capable of delivering challenging compounds, ie small molecule STING agonists, subcutaneously through electrostatic coupling, highlighting its potential to revolutionize cancer vaccinology. Citation Format: Max Wang, Miran Choi, Bin Zhang, Nathan Gianneschi. Proteomimetic polymers limit tumor growth in multiple models via potent antigen-specific T cell activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 481.