Functional Polyolefins Research Articles

Hydroesterification of Polycyclooctene to Access Linear Ethylene Ethyl Acrylate Copolymers as a Step Toward Polyolefin Functionalization

Hydroesterification of Polycyclooctene to Access Linear Ethylene Ethyl Acrylate Copolymers as a Step Toward Polyolefin Functionalization

Rare-Earth Metallocenes for Polymerization of Olefins and Conjugated Dienes: From Fundamental Studies to Olefin Block Copolymers.

The various steps in the mechanism of olefin polymerizations mediated by neutral rare-earth metallocene complexes are discussed. The complexes are either trivalent hydride and alkyl rare-earth compounds or divalent metallocenes that are activated by the monomer via an oxidation step. The stereospecific polymerizations of conjugated dienes based on the association of a cationic metallocene complex and an alkylaluminum and the polymerization mechanism based on monomer insertion into an aluminum-carbon bond are also discussed. The exploitation of metallocene complexes for the copolymerization of olefins with conjugated dienes is the subject of a third part of this review. The synthesis of new elastomers called ethylene butadiene rubber (EBR) is highlighted. Finally, the use of rare-earth metallocenes in macromolecular engineering is detailed. This includes the synthesis of functional polyolefins and block copolymers including thermoplastic elastomers.

Dehydrogenated Polyethylene from Discarded Plastics as a Synthon for Functional Polyolefins

Dehydrogenated Polyethylene from Discarded Plastics as a Synthon for Functional Polyolefins

Recent Advances in Nickel Catalysts with Industrial Exploitability for Copolymerization of Ethylene with Polar Monomers.

The direct copolymerization of ethylene with polar monomers to produce functional polyolefins continues to be highly appealing due to its simple operation process and controllable product microstructure. Low-cost nickel catalysts have been extensively utilized in academia for the synthesis of polar polyethylenes. However, the development of high-temperature copolymerization catalysts suitable for industrial production conditions remains a significant challenge. Classified by the resultant copolymers, this review provides a comprehensive summary of the research progress in nickel complex catalyzed ethylene-polar monomer copolymerization at elevated temperatures in the past five years. The polymerization results of ethylene-methyl acrylate copolymers, ethylene-tert-butyl acrylate copolymers, ethylene-other fundamental polar monomer copolymers, and ethylene-special polar monomer copolymers are thoroughly summarized. The involved nickel catalysts include the phosphine-phenolate type, bisphosphine-monoxide type, phosphine-carbonyl type, phosphine-benzenamine type, and the phosphine-enolate type. The effective modulation of catalytic activity, molecular weight, molecular weight distribution, melting point, and polar monomer incorporation ratio by these catalysts is concluded and discussed. It reveals that the optimization of the catalyst system is mainly achieved through the methods of catalyst structure rational design, extra additive introduction, and single-site catalyst heterogenization. As a result, some outstanding catalysts are capable of producing polar polyethylenes that closely resemble commercial products. To achieve industrialization, it is essential to further emphasize the fundamental science of high-temperature copolymerization systems and the application performance of resultant polar polyethylenes.

Functionalization of Polyolefins with Maleic Anhydride by Flash Reactive Extrusion: Processing and Applications

Functionalization of Polyolefins with Maleic Anhydride by Flash Reactive Extrusion: Processing and Applications

Unveiling the Detailed Mechanism and Origins of Chemo-, Regio-, and Stereoselectivity of Rare-Earth Catalyzed Alternating Copolymerization of Polar and Nonpolar Olefins.

The direct copolymerization of polar and nonpolar olefins is of great interest and significance, as it is the most atom-economical and straightforward strategy for the synthesis of functional polyolefin materials. Despite considerable efforts, the precise control of monomer-sequence and their regio- and stereochemistry is full of challenges, and the related mechanistic origins are still in their infancy to date. Herein, the mechanistic studies on the model reaction of Sc-catalyzed co-syndiospecific alternating copolymerization of anisylpropylene (AP) and styrene were performed by DFT calculations. The results suggest that the subtle balance between electronic and steric factors plays an important role during monomer insertions, and a new amino-dissociated mechanism was proposed for AP insertion at chain initiation. AP insertion follows the 2,1-si-insertion pattern, which is mainly controlled by steric factors caused by the restricted MeO···Sc interaction. As for styrene insertion, it prefers the 2,1-re-insertion manner and its regio- and stereoselectivities are influenced by steric repulsions between the inserting styrene and the polymer chain or the ligand. More interestingly, it is found that the alternating monomer-sequence is mainly determined by the "steric matching" principle, which is quantitatively expressed by the buried volume of the metal center of the preinserted species. The concept of steric pocket has been successfully applied to explain the different performances of several catalysts and other alternating copolymerization reactions. The insightful mechanistic findings and the quantitative steric pocket model present here are expected to promote rational design of new rare-earth catalysts for developing regio-, stereo-, and sequence-controlled copolymerization of specific polar and nonpolar olefins.

Chain-end functionalization of polyolefins prepared by α-diimine nickel catalysts using transfer to organometallic compounds

A method for chain-end functionalization is described for branched polyolefins obtained by living olefin polymerization initiated by α-diimine nickel catalysts. The method relies on transmetalation of living polymer chains from nickel growing centres to excess organozinc, organomagnesium or organoaluminium transfer agents followed by oxidation. Hydroxy-terminated polyolefins were obtained with efficiencies going from 25 to 99%. The resulting end-functionalized polyolefins were characterized by MALDI-TOF MS and employed as macroinitiators for ring opening polymerization of ε-caprolactone to provide amphiphilic block copolymers.

(General Student Poster Award Winner - 2nd Place) Electrochemical Routes for Polymer Upcycling

Approximately 380 million tons of plastic are produced annually, and it is projected to rise to nearly 1.1 billion by 2050 [1]. The largest fraction of such waste consists of polyethylene (PE) and polypropylene (PP), which commonly require energy-intensive methods to achieve depolymerization (such as pyrolysis and hydrogenolysis) due to their remarkable thermodynamic stability. Electrochemical methods are a promising alternative for polymer upcycling as they can utilize renewable energy to create an external potential, overcoming the thermodynamic constraints that the C-C bond cleavage endothermicity imposes on low-temperature polymer conversion. They also offer improved chemical process control by manipulating the electrode potential and minimizing the use and storage of hazardous reagents. Electrochemistry provides a broad range of opportunities for establishing green routes to converting plastic into valuable products.Botte's group is investigating electrochemical approaches to convert polyolefins into valuable products like fuels and fatty acids [2]. Our findings indicate that an electrocatalyst in concert with controlled ionic strength and applied potential enable the selective functionalization of polyolefins and their defragmentation towards target molecules regardless of impurities present in the polymer. In this presentation, we will discuss results of the electrochemical functionalization and deconstruction of low-density polyethylene implementing transition metal electrocatalysts. Acknowledgments: The authors would like to acknowledge the financial support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Upcycling of Polymers Program, under Award DE-SC0022307[1] J. E. Rorrer, C. Troyano-Valls, G. T. Beckham, and Y. Román-Leshkov, "Hydrogenolysis of Polypropylene and Mixed Polyolefin Plastic Waste over Ru/C to Produce Liquid Alkanes," ACS Sustainable Chemistry & Engineering, vol. 9, no. 35, pp. 11661-11666, 2021/09/06 2021, doi: 10.1021/acssuschemeng.1c03786.[2] G. G. Botte, "Process for the Electrochemical Up-Cycling of Plastics (US Pending Patent)," U.S. Patent 63040929, 2020.

Dopamine-Based Copolymer Bottlebrushes for Functional Adhesives: Synthesis, Characterization, and Applications in Surface Engineering of Antifouling Polyethylene.

Nonpolar materials like polyolefins are notoriously challenging substrates for surface modification. However, this challenge is not observed in nature. Barnacle shells and mussels, for example, utilize catechol-based chemistry to fasten themselves onto all kinds of materials, such as boat hulls or plastic waste. Here, a design is proposed, synthesized, and demonstrated for a class of catechol-containing copolymers (terpolymers) for surface functionalization of polyolefins. Dopamine methacrylamide (DOMA), a catechol-containing monomer, is incorporated into a polymer chain together with methyl methacrylate (MMA) and 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM). DOMA serves as adhesion points, BIEM provides functional sites for subsequent "grafting from" reactions, and MMA provides the possibility for concentration and conformation adjustment. First, the adhesive capabilities of DOMA are demonstrated by varying its content in the copolymer. Then, terpolymers are spin-coated on model Si substrates. Subsequently, the atom transfer initiator (ATRP) initiating group is used to graft a poly(methyl methacrylate) (PMMA) layer from the copolymers, with 40% DOMA content providing a coherent PMMA film. To demonstrate functionalization on a polyolefin substrate, the copolymer is spin-coated on high-density polyethylene (HDPE) substrates. A POEGMA layer is grafted from the ATRP initiator sites on the terpolymer chain on the HDPE films to provide antifouling characteristics. Static contact angle values and Fourier transform infrared (FTIR) spectra confirm the presence of POEGMA on the HDPE substrate. Finally, the anticipated antifouling functionality of grafted POEGMA is demonstrated by observing the inhibition of nonspecific adsorption of the fluorescein-modified bovine serum albumin (BSA) protein. The poly(oligoethylene glycol methacrylate) POEGMA layers grafted on 30% DOMA-containing copolymers on HDPE show optimal antifouling performance exhibiting a 95% reduction of BSA fluorescence compared to nonfunctionalized and surface-fouled polyethylene. These results demonstrate the successful utilization of catechol-based materials for functionalizing polyolefin surfaces.

Research and synthesis of polyolefins materials

Polyolefins are widely used in our lives, such as food packaging materials, agricultural films, and lubricants, but the lack of polar groups that can make polyolefins compatible with other types of materials has limited the use of polyolefins. This has been a challenging and highly concerned issue in academia and industry. Therefore, it is great significance that we introduce polar groups into polyolefins to improve the use of performance to synthesize functional polyolefins. In this paper, we introduce the direct catalytic polymerization of polar α olefin monomers using rare earth catalysts, and the experimental data shows that we have obtained a higher molecular weight and better selectivity polar α olefin monomer of homopolymer. Subsequently, we determined the optimal reaction conditions for the synthetic polymer through screening of different reaction conditions.

Organosilicon‐functionalized polyolefins, a kind of designable and versatile polymer: From preparation to applications

AbstractFunctionalization of polyolefins has been a challenging but promising issue since their invention, with the promise of retaining inherent properties and overcoming the low reactivity and poor compatibility. Organosilicons are widely used for polymer modification to improve thermal stability, hydrophobicity, compatibility, and permeability. Since the advent of alkoxysilane‐grafted polyethylene in 1960s, organosilicon‐functionalized polyolefins (Si‐PO) have been extensively prepared, investigated, and developed. The structure of Si‐PO is designable due to the flexible chemistry of organosilicons; crosslinked, long chain branched, and star‐shaped polyolefins are available after the introduction of alkoxysilanes, chlorosilanes, hyrdosilanes, or alkylsilanes into polyolefins, and generally these polymers are more compatible to fillers than commercial polyolefins due to stronger interaction. In addition, functionalization of polyolefins with stable organosilicon components such as polysiloxane and polysilsesquioxane can improve thermostability, hydrophobicity, gas permeability, and aging resistance; such polyolefins are usually grafted or block polymers. In this review, Si‐PO is classified according to the functional organosilicon component, namely alkoxysilane, chlorosilane, hydrosilane, alkylsilane, polysiloxane, and polysilsesquioxane; their preparations are discussed minutely and summarized with manifold examples. Silicon‐containing structures impart the unique properties of organosilicons to polyolefins; applications of Si‐PO as compatibilizers, processing aids, battery separators, and separating membranes have been widely reported and are discussed here.

Proximity-Driven Synergic Copolymerization of Ethylene and Polar Monomers

Coordination copolymerization of ethylene and polar monomers is a promising strategy for preparing structurally well-defined functional polyolefin. However, the poisonous effect of polar groups on employed catalysts is the main obstacle to be overcome. To mimic the synergistic catalysis of multinuclear metal compounds in nature, herein, we report the copolymerization of ethylene with a series of unprotected polar monomers containing oxygen, nitrogen, and sulfur atoms using binuclear half-sandwich scandium complexes C1-Sc2 and C2-Sc2 bearing −CH2– and −CH2CH2– linkers, respectively. In the copolymerization of ethylene and para-methoxystyrene (pMOS), C1-Sc2 and C2-Sc2 exhibit 13 and 7 times greater activities, respectively, than the mononuclear analogue Sc1. For the polar olefins having a butylene spacer, the activities follow the trend C1-Sc2 > C2-Sc2 > Sc1, whereas for the polar olefins that are shorter or longer than the butylene spacer, C2-Sc2 shows the highest activity. Moreover, the synergic effects and the cooperative mechanism for ethylene and pMOS copolymerization with C1-Sc2 were supported by DFT calculations.

Palladium-catalyzed synthesis of oil-based functionalized polyolefins

In this study, we used a palladium catalyst to catalyze the copolymerization of vegetable oil-based monomers with ethylene to prepare functional polyolefins.

Photoinduced iron-catalyzed C-H alkylation of polyolefins.

Chemically introducing diverse polar groups into polyolefins via carbon-hydrogen bond alkylation with polar olefins is of substantial value in the synthesis of next-generation lightweight thermoplastics, which is still underdeveloped. In this work, we report a new approach for efficient carbon-hydrogen bond alkylation in commodity polyolefins using photoinduced iron catalysis. Various polyolefins could be functionalized with broad scope. Polar groups could be incorporated in a single step. The controllable synthesis of multi-polar functional polyolefins could be achieved by a designed module-assembled process. Remarkably, even low levels of functionalization could upcycle the polyolefin materials to exhibit unusual physical properties, such as enhancement of the transparencies, strains, stresses at break of the materials, and hydrophilicity.

Stereoselective Copolymerization of Olefin with Polar Monomers to Access Stereoregular Functionalized Polyolefins

Introducing polar functionalities to polyolefins such as polyethylene and polypropylene is highly desirable for improving physical properties of the otherwise non-polar material. The synthesis of stereoregular functionalized polyolefins, however, has been a relatively underdeveloped area compared to that of functionalized polyethylene because of the lack of suitable catalysts that tolerate polar groups while possessing stereoselectivity. This review summarizes recent advances concerning the access to stereoregular functionalized polyolefins, including synthetic strategies such as post-functionalization, chain transfer and direct copolymerization methods. The focus of the review lies in the copolymerization approach, in which various polar comonomers and versatile stereoselective polymerization catalysts based on both early and late transition metals are involved. Polymer properties and potential applications for these materials are simply discussed.1. Introduction2. Reactive-Intermediate-Polymer Approach to Stereoregular Functionalized Polypropylene3. Preparation of Stereoregular Functionalized Polypropylene by Chain-End Functionalization4. Stereoselective Copolymerization of Propylene and Polar Monomers by Early Transition Metal Catalysts5. Stereoselective Copolymerization of Propylene with Polar Monomers by Late Transition Metal Catalysts6. Stereoselective Copolymerization of α-Olefins with Polar Monomers7. Stereoselective Homopolymerization of Polar Monomers8. Polymer Properties and Potential Applications9. Conclusion and Outlook

Tailor-Made Functional Polyolefins of Complex Architectures: Recent Advances, Applications, and Prospects

Polyolefins play a crucial role in the polymer industry because of their low-cost monomers and well-established production processes. Recent years have witnessed tremendous progress in direct and tandem copolymerization strategies that provide an opportunity of developing polyolefins bearing polar groups with distinctive architectures and properties. In this perspective, we first highlight new routes for the proficient synthesis of tailor-made functional polyolefins and briefly discuss their designing tactics. Then, we attempt to categorize these, recently appeared in the literature, innovative functional polyolefins on the basis of their applications. The prospected future applications of polar olefin copolymers include biomedical materials, catalysts, energy storage devices, and conductive polymers, which open up new arenas and paradigms for academic research and industrial products development. Critical issues concerning intelligent functional polyolefins and green chemistry are discussed, too.

Cover Picture: One‐For‐All Polyolefin Functionalization: Active Ester as Gateway to Combine Insertion Polymerization with ROP, NMP, and RAFT (Angew. Chem. Int. Ed. 33/2022)

A polyolefin active ester exchange (PACE) process was developed for polyolefin-containing block copolymer synthesis and serves as a bridge connecting coordination–insertion polymerization to multiple controlled polymerization methods. As reported by Krzysztof Matyjaszewski, Eva Harth et al. in their Research Article (e202205931), PACE allows for the synthesis of hybrid materials that comprise olefins and ester, styrene, vinylic, acrylate, and acrylamide segments with a broad window for tunability. Nano-objects with higher-order morphologies can be obtained directly via RAFT-mediated PISA.

Titelbild: One‐For‐All Polyolefin Functionalization: Active Ester as Gateway to Combine Insertion Polymerization with ROP, NMP, and RAFT (Angew. Chem. 33/2022)

Ein aktiver Polyolefin-Esteraustausch (PACE) wurde für die Synthese polyolefinhaltiger Blockcopolymere entwickelt. Der Prozess verknüpft die Koordinations-Insertions-Polymerisation mit multiplen kontrollierten Polymerisationsmethoden. Wie Krzysztof Matyjaszewski, Eva Harth et al. in ihrem Forschungsartikel (e202205931) berichten, ermöglicht PACE die Synthese von Hybridmaterialien, die Olefine sowie Ester-, Styrol-, Vinyl-, Acrylat- und Acrylamidsegmente enthalten und in einem breiten Fenster gezielt abgestimmt werden können. Nanoobjekte mit Morphologien höherer Ordnung können direkt über RAFT-vermittelte PISA erhalten werden.

One‐For‐All Polyolefin Functionalization: Active Ester as Gateway to Combine Insertion Polymerization with ROP, NMP, and RAFT

AbstractThis work develops the Polyolefin Active‐Ester Exchange (PACE) process to afford well‐defined polyolefin–polyvinyl block copolymers. α‐Diimine PdII‐catalyzed olefin polymerizations were investigated through in‐depth kinetic studies in comparison to an analog to establish the critical design that facilitates catalyst activation. Simple transformations lead to a diversity of functional groups forming polyolefin macroinitiators or macro‐mediators for various subsequent controlled polymerization techniques. Preparation of block copolymers with different architectures, molecular weights, and compositions was demonstrated with ring‐opening polymerization (ROP), nitroxide‐mediated polymerization (NMP), and photoiniferter reversible addition–fragmentation chain transfer (PI‐RAFT). The significant difference in the properties of polyolefin–polyacrylamide block copolymers was harnessed to carry out polymerization‐induced self‐assembly (PISA) and study the nanostructure behaviors.

One-For-All Polyolefin Functionalization: Active Ester as Gateway to Combine Insertion Polymerization with ROP, NMP, and RAFT.

This work develops the Polyolefin Active-Ester Exchange (PACE) process to afford well-defined polyolefin-polyvinyl block copolymers. α-Diimine PdII -catalyzed olefin polymerizations were investigated through in-depth kinetic studies in comparison to an analog to establish the critical design that facilitates catalyst activation. Simple transformations lead to a diversity of functional groups forming polyolefin macroinitiators or macro-mediators for various subsequent controlled polymerization techniques. Preparation of block copolymers with different architectures, molecular weights, and compositions was demonstrated with ring-opening polymerization (ROP), nitroxide-mediated polymerization (NMP), and photoiniferter reversible addition-fragmentation chain transfer (PI-RAFT). The significant difference in the properties of polyolefin-polyacrylamide block copolymers was harnessed to carry out polymerization-induced self-assembly (PISA) and study the nanostructure behaviors.