Diels-Alder polymers, reaction

The metathesis polymerisation of dicyclopentadiene, an inexpensive monomer (commercially available cyclopentadiene dimer produced by a Diels-Alder addition reaction containing ca 95 % endo and ca 5 % exo form), leads to a polymer that may be transformed into a technically useful elastomer [144-146, 179] and thermosetting resin [180,181]. The polymerisation has characteristics that make it readily adaptable to the reaction injection moulding ( rim ) process [182], The main feature of this process comes from the fact that the polymerisation is carried out directly in the mould of the desired final product. The active metathesis catalyst is formed when two separate reactants, a precatalyst (tungsten-based) component and an activator (aluminium-based) component, are combined. Monomer streams containing one respective component are mixed directly just before entering the mould, and the polymerisation into a partly crosslinked material takes place directly in this mould (Figure 6.5) [147,168,183-186],... 

A facile synthesis of enantiopure tricyclic furyl derivatives employing 4-vinyl-2,3-dihydrofuran via Diels-Alder cycloaddition reaction was reported <02TL7983>. A new capture-ROMP-release procedure for chromatography-free purification of N-hydroxysuccinimide Mitsunobu reactions was reported by Hanson, who used a Mitsunobu reaction to capture a variety of alcohols onto a norbomenyl A-hydroxysuccinirmde monomer. Treatment of this monomer under ROM-polymerization then generated a water-soluble polymer that was readily separable from other by-products. Subsequent reaction with hydrazine was utilized to release the O-alkylhydroxylamines in good purity from the water-soluble polymer <020L1007>. 

Several di-dienes have been successfully utilized in copolymerization reactions with di-dienophiles. The diene 2-hydroxymethylbutadiene offers a functional handle by which two butadiene portions may be linked to form a di-diene (5). Copolymerization reactions of these di-dienes with a series of fcis-maleimides and quinone in refluxing dime-thylformamide afford Diels-Alder polymers with a range of physical properties. 

Three unique di-diene have been utilized by Meek (9, 10) in the preparation of Diels-Alder copolymers. Reaction of 1,8-diphenyl-octatetraene with ftts-maleimides in refluxing chloroform for several days affords high yields of polymers with softening temperatures well over 300°, but low intrinsic viscosities. The copolymerization of 1,5-di(9-anthryl)-l,4-pentadiene-3-one and anthralazine with fo s-maleimides employs the diene nature of anthracene to obtain polymers with... 

Since the fo s-cyclopentadienyl compoimds I—IV may also function as di-dienes, Dieles-Alder copolymerization reactions with di-dienophiles lead to high molecular weight polymers. In the Diels-Alder copolymerization reactions of these di-dienes, it is not necessary that a 1 1 ratio of monomers be included in the reaction mixture. The di-dienes will also homopolymerize and may serve in the capacity as di-diene, a di-dieno-phile and a dienophilic diene. A copolymer of a, a -fo s-cyclopentadienyl- -xylene and 4-phenylene-i>ts-maleimide has been reported in which... 

This finds some support in a comparison of solution viscosities with polymerization time of a few isolated cases of Diels-Alder polymerization reactions. In the polymerization of 2,5-dimethylene-3,4-diphenylcyclo-pentadieneone with N.N -hexamethylene-fo s-maleimide, the reduced viscosity of the polymer increases from 0.97 after 1 hr to 1.20 after six hours (7). It is necessary to assume that the rate controlling step in this reaction is neither the formation of the initial adduct nor the loss of carbon monoxide. The inherent viscosity of the l,6-6is-(cyclopenta-dienyl)hexane-quinone copolymer increases from 0.10 after sixteen hours to 0.12 after twenty four hours reaction time in refluxing benzene (14). 

Kuramoto N, Hayashi K, Nagai K (1994) Thermoreversible reaction of Diels-Alder polymer composed of difurufuryladipate with bismaleimidodiphenylmethane. J Polym Sci A Polym Chem 32 2501-2504... 

Diels Alder polymers can be obtained via the cyclo-pentadienone route [3,17]. New CPDs were synthesized according to the following reaction scheme [18] ... 

Diels-Alder polymers n. Polymers created as a result of a Diels-Alder reaction, by which a 1,3-diene reacts via addition to another unsaturated molecule (the dienophile) to form a cyclic adduct. Morrison RT, Boyd RN (1992) Organic chemistry, 6th edn. Prentice-Hall, Englewood Cliffs, NJ. Smith MB, March J (2001) Advanced organic chemistry, 5th edn. John Wiley and Sons, New York. 

Anionic and Cationic Polymerizations o Radical Polymerization Advances o Coordination Polymerizations 0 Step-Growth Polymerization Advances 0 Synthesis of Tactic Polymers o Stereoblock Copolymers o Dispersion Polymerizations o Cellulosic Graft Copolymers o Diels-Alder Polymer Forming Reactions o A New Path To Phenolic Resins o Nitrogen Heterocycle Polymerizations o Optically Active Polymers o Poly (Phenylene Sulfide) o Poly (Aryl Ethers) o (Poly (Aryl Ether Sulfones) o Epoxy and Isocyanate Resin Replacement o Azlactone Functionalized Oligomers o Epoxy Resin-Isocyanate Reactions o Chelating Polymers o Oxazoline Functionalized Polymers o Poly (Alkyl Methacrylates) o Macromers... 

The hydrocarbon resins can be produced by a simple thermal polymerization process (48-50) or by Lewis acid catalyzed reaction (51). The thermal process is carried out at a high temperature in the range of 200-280°C and a reactor pressure above 300 psig. At temperatures below 200°C, the Diels-Alder polymers are formed. They are not desirable in most resins because they are insoluble in aromatic solvents. If reaction temperature exceeds 280°C, decomposition of the resins would occur. 

Diels-Alder click reactions have been successfully used for the preparation of well-de ned star polymers. Devise methodologies using this route to prepare 3-arm star polymers with uniform arms, core-As, where A is (a) poly(ethylene glycol), (b) poly(methyl methacrylate), and (c) poly(tert-butyl... 

Tunca et al. [27, 28,38] reported in a series of papers on a multi-click approach for the preparation of brush copolymers. The backbone consisted of homopolymers, statistical polymers, or block copolymers from ONBEs with orthogonal side groups for Diels-Alder click reaction [27,28,38], azide/alkyne click reaction, [27, 28, 38] and nitroxide coupling [27]. In a grafting-to approach, maleimide-or ONBE-functionalized polymers (PEG, P BA, PMMA (56)) were attached by Diels-Alder click reaction with the anthracene groups pendant at the polymer backbone (55) (Scheme 9.8b). PCL chains were attached by an azide/alkyne click reaction, while a combination of Diels-Alder and azide/alkyne click reaction allowed the synthesis of graft copolymers with PS-/ -PEG-, PS-h-PMMA-, or PS-/ -P BA side chains. 

Reactions between a diene and a dienophile yielding cyclohexene derivatives through carbon-carbon or carbon-heteroatom bond formation are referred to as Diels-Alder (DA) reactions. The concerted [4 + 2] cycloaddition was first described in 1928 by Diels and Alder, ° and can be adapted for the efficient conjugation of peptides and proteins to synthetic polymers. Despite being recognized as highly selective and additive-free, DA reactions require elevated temperatures to obtain the desired product. Furthermore, the reversibility of the reaction limits its application in materials science. ... 

Some other highly efficient cycloaddition reactions have been used for polymer end-group modification and polymer-polymer conjugation. These include an additive-free version of the hetero Diels-Alder (HDA) reaction or the nitrile-imine-mediated tetrazole-ene cycloaddition (NITEC), the latter only requiring photoirradiation. Both techniques meet the criteria to be considered bioorthogonal reactions and can be performed under mild reaction conditions. As such, these reactions should also be applicable for the preparation of bioconjugates. 

ARU 11a] Arumugam S., Orski S.V., Locklin J. et al, Photoreactive Polymer Bmshes for High-Density Patterned Surface Derivatization Using a Diels-Alder Photoclick Reaction , Journal of the American Chemical Society, vol. 134, pp. 179-182, 2011. 

---