Preparation of ABC miktoarm star terpolymer containing poly(ethylene glycol), polystyrene, and poly(tert-butylacrylate) arms by combining diels-alder reaction, atom transfer radical, and stable free radical polymerization routes

Trends in the Diels-Alder reaction in polymer chemistry

The Diels-Alder (DA) reaction is regarded as quite a useful strategy in organic and macromolecular syntheses. The reversibility of this reaction and the advent of self-repair technology, as well as other applications in controlled macromolecular architectures and crosslinking, have strongly boosted the research activity, which is still attracting a huge interest in both academic and industrial research. The DA reaction is a simple and scalable toolbox. Though it is well-established that furan/maleimide is the most studied diene/dienophile couple, this perspective article reports strategies using other reversible systems with deeper features on other types of diene/dienophile pairs being either petro-sourced (cyclopentadiene, anthracene) or bio-sourced (muconic and sorbic acids, myrcene and farnesene derivatives, eugenol, cardanol). This review is composed of four sections. The first one briefly recalls the background on the DA reactions involving cyclodimerizations, dienes, and dienophiles, parameters affecting the reaction, while the second part deals with the furan/maleimide reaction. The third one deals with petro-sourced and bio-sourced (or products becoming bio-sourced) reactants involved in DA reactions are also listed and discussed. Finally, the authors' opinion is given on the potential future of the crosslinking-decrosslinking reaction, especially regarding the process (e.g., key temperatures of decrosslinking) or possibly monocomponents. It presents both fundamental and applied research on the DA reaction and its applications.

A healable thermo-reversible functional polymer prepared via RAFT polymerization and ultrafast ‘click’ chemistry using a triazolinedione derivative

The synthesis of a thermo-reversible self-healable functional polymer based on the indole functionality via RAFT polymerization followed by an ultrafast Alder-ene ‘click’ reaction using 1,2,4-triazoline-3,5-dione (TAD) chemistry is reported.

Amphiphilic functional block copolymers bearing a reactive furfuryl group via RAFT polymerization; reversible core cross-linked micelles via a Diels–Alder “click reaction”

Amphiphilic BCPs, PFMA-b-PPEGMA were prepared via RAFT polymerization. They were self-assembled into micelles in aqueous medium with a hydrophobic PFMA core and hydrophilic PPEGMA corona. Core cross-linked micelles were prepared via the DA reaction.

Synthesis of ABB′ and ABC star copolymers via a combination of NMRP and ROP reactions

Well-defined miktoarm star copolymers (ABB′ and ABC) were synthesized via a combination of NMRP and ROP using N-(2-hydroxyethyl)maleimide as the branching molecule.

Maleimide Glycidyl Ether: A Bifunctional Monomer for Orthogonal Cationic and Radical Polymerizations

A novel bifunctional monomer, namely maleimide glycidyl ether (MalGE), prepared in a four-step reaction sequence is introduced. This monomer allows for selective (co)polymerization of the epoxide group via cationic ring-opening polymerization, preserving the maleimide functionality. On the other hand, the maleimide functionality can be copolymerized via radical techniques, preserving the epoxide moiety. Cationic ring-opening multibranching copolymerization of MalGE with glycidol was performed, and a MalGE content of up to 24 mol% could be incorporated into the hyperbranched polymer backbone (Mn = 1000-3000 g mol(-1)). Preservation of the maleimide functionality during cationic copolymerization was verified via NMR spectroscopy. Subsequently, the maleimide moiety was radically crosslinked to generate hydrogels and additionally employed to perform Diels-Alder (DA) "click" reactions with (functional) dienes after the polymerization process. Radical copolymerization of MalGE with styrene (Mn = 5000-9000 g mol(-1)) enabled the synthesis of a styrene copolymer with epoxide functionalities that are useful for versatile crosslinking and grafting reactions.

Well-defined polymethylene-based block co/terpolymers by combining anthracene/maleimide diels–alder reaction with polyhomologation

Well-defined co/terpolymers of polymethylene (PM) with poly(d,l-lactide) (PLA), polycaprolactone (PCL) and polyethylene glycol (PEG) were synthesized by combining polyhomologation, anionic ring opening polymerization and anthracene(Ant)/maleimide(MI) Diels–Alder reaction.

Model Diels-Alder Studies for the Creation of Amphiphilic Cross-Linked Networks as Healable, Antibiofouling Coatings

Diels-Alder (DA) chemistry was used in the construction of amphiphilic cross-linked polymer networks comprised of furan-functionalized hyperbranched fluoropolymers and maleimide-functionalized linear poly(ethylene glycol)s, which were designed as antibiofouling coatings capable of repair. Discrete molecules and a linear polymer analog were studied as model systems to understand the nature of the thermally reversible [4 + 2] cycloaddition reaction involving a tetrafluorobenzylfuranyl ether unit, which was part of the structure for the incorporation of the DA functionalities into the composite network materials. Atomic force microscopy confirmed the complex, nanoscopically resolved topography needed for antibiofouling. Bright field and fluorescence imaging monitored healing at damage sites as well as the ability of the coatings to resist protein adsorption.

Constructing star polymersvia modular ligation strategies

Over recent years, modular ligation reactions—some of which adhere to the click criteria—have enabled the synthesis of a variety of star polymers via efficient polymer–polymer conjugations. The copper catalyzed azide–alkyne cycloaddition (CuAAC), Diels–Alder (DA), and Hetero Diels–Alder (HDA) reactions are reviewed here in detail for the facile generation of various macromolecular star topologies.

"Click chemistry" in tailor-made polymethacrylates bearing reactive furfuryl functionality: a new class of self-healing polymeric material

This investigation reports the effective use of the Diels-Alder (DA) reaction, a "click reaction" in the preparation of thermally amendable and self-healing polymeric materials having reactive furfuryl functionality. In this case, the DA and retro-DA (rDA) reactions were carried out between the tailor-made homo- and copolymer of furfuryl methacrylate prepared by atom-transfer radical polymerization and a bismaleimide (BM). The kinetic studies of DA and rDA reactions were carried out using Fourier transform infrared spectroscopy. The DA polymers were insoluble in toluene at room temperature. When the DA polymers were heated at 100 degrees C in toluene, it was soluble. This is because of the cleavage between furfuryl functionality and BM. The chemical cross-link density was determined by the Flory-Rehner equation. The cross-linked polymer showed much greater adhesive strength at room temperature, but the adhesive strength was quite low at higher temperature. The self-healing capability was studied by using scanning electron microscopy analysis. The thermal and dynamic mechanical properties of the thermally amendable cross-linked materials were investigated by thermogravimetric analysis and dynamic mechanical analysis.