Selective single ring‐opening polymerization of spiroorthoesters with aluminium (III) acetylacetonate

Chikaoka, Satoyuki; Takata, Toshikazu; Endō, Takeshi

doi:10.1002/pola.1990.080281116

Cited by 18 publications

(19 citation statements)

References 9 publications

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“…We have developed bicyclic orthoesters (BOEs) and spiro orthoesters (SOEs) as expandable monomers, which undergo a cationic double ring-opening polymerization at high temperature (A100 8C) (Scheme 1) 2) . Hall Jr. et al and we have also reported that BOEs and SOEs afford single ring-opened polymers below 0 8C 3,4) . Recently, we have observed the cationic equilibrium polymerization behavior of BOEs and SOEs 5,6) .…”

Section: Introductionsupporting

confidence: 77%

Reversible crosslinking-decrosslinking of polymers having bicyclo orthoester moieties in the side chains

Hitomi

Sanda

Endo³

1999

Macromol. Chem. Phys.

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SUMMARY: Radical polymerizations of methacrylate-and styrene-based bicyclo orthoesters (BOEs), and their copolymerization with methyl methacrylate and styrene were carried out with 2,29-azoisobutyronitrile (AIBN, 5 mol-%) as an initiator in N,N-dimethylformamide (DMF, 2 M) at 708C for 15 h to afford the corresponding polymers in 64 -96% yields having BOE moieties in the side chains. Crosslinking of the polymers was carried out in the presence of BF 3 N OEt 2 (3 mol-%) as a cationic catalyst in CH 2 Cl 2 . The yield of the crosslinked polymer increased with increasing initial concentration of the polymer and increasing crosslinking temperature. Decrosslinking of the crosslinked polymers was carried out in the presence of trifluoroacetic acid (TFA, 5 mol-%) as a cationic catalyst in CH 2 Cl 2 to regenerate the starting linear polymers. The recovery of the starting linear polymer increased with decreasing concentration of the initially crosslinked polymer and with increasing decrosslinking temperature.

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Section: Introductionsupporting

confidence: 77%

Reversible crosslinking-decrosslinking of polymers having bicyclo orthoester moieties in the side chains

Hitomi

Sanda

Endo³

1999

Macromol. Chem. Phys.

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“…SOE opening of the seven-membered ether ring (Scheme 2)." In this article, we report [ l ] cationic polymerization of SOEs at low temperature to afford single ring-opened poly(cyc1ic orthoester)s, [2] the polymerization is one of the equilibrium polymerizations, [3] reversible crosslinkingdecrosslinking system between bifunctional SOEs and network polymers utilizing the equilibrium polymerization of SOEs, and [4] reversible crosslinking-decrosslinking system between linear polymers with SOE moieties and network polymers.…”

Section: Methodsmentioning

confidence: 99%

Cationic equilibrium ring‐opening polymerization of bicyclic monomers and its application to chemical recycling

Endō

Sanda

1998

Macromolecular Symposia

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SUMMARYSpiro orthoesters give poly(cyc1ic 0rthoester)s by single ring-opening polymerization in the presence of acid catalysts, and this process undergoes the equilibrium polymerization. We have applied the function of equilibrium polymerization to chemical recycling of polymeric materials. Crosslinked poly(cyc1ic orthoester)s, prepared by radical additions of poly(cyc1ic 0rthoester)s possessing exomethylene groups and dithiols, efficiently decrosslinked to bifunctional spiro orthoesters in the presence of CF3C0,H in CqCl,. The dithiol-linked bifunctional spiro orthoester monomers, prepared by the radical additions of spiro orthoester possessing exomethylene group and dithiols, afforded the corresponding crosslinked polymers in the presence of CF3C0,H as a catalyst in bulk. The decrosslinking of the obtained crosslinked polymer proceeded quantitatively to obtain the corresponding bifunctional monomer at room temperature in CH& Further, an acid-catalyzed reversible crosslinking-decrosslinking of a polymer having a spiro orthoester group in the side chain was carried out. The copolymer obtained by the radical copolymerization of 2-methylene-l,4,6-trioxaspiro[4.6]undecane with acrylonitrile was treated with CF3C0,H at -10 "C in CH,C1, to afford the crosslinked polymer quantitatively. The crosslinked polymer was then treated with CF3C02H at room temperature at a low concentration in CH,Cl, to recover the original polymer. IntroductionDevelopment of an excellent method for recycling of polymeric materials is an extremely important subject in recent polymer science and technology.') Among the few technologies for recycling, chemical recycling may be the most important and essential. Spiro orthoesters (SOEs) polymerize with cationic catalysts to yield poly(ether-ester)s via double ring-opening polymerization (Scheme 1);) and no shrinkage in volume is observed on this polymerization. This may be explained by the compensation effect by the double ring-opening in the decrease in free volume due to nearing molecules from van der Wads distance to covalent distance. Recently, we have found that SOE (1) polymerizes with Al(acac), as a catalyst at room temperature to give poly(cyc1ic orthoester) (2) which can be regarded as being formed via a selective single ring-

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“…6 Spiro orthoesters (SOEs, 1) undergo cationic polymerization at high temperature (Ͼ100°C) via a double ring-opening process to give poly(ether esters) (2) as illustrated in Scheme 1. 7 Recently, we have found that the cationic polymerization of SOEs consisting of a seven-membered ether ring and a five-membered acetal ring afford poly(cyclic orthoesters) (3) at low temperature (Ͻ10°C) via a single ring opening of the ether ring.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and cationic ring-opening polymerization of mono- and bifunctional spiro orthoesters containing ester groups and depolymerization of the obtained polymers: An approach to chemical recycling for polyesters as a model system

Yoshida

Sanda

Endō

1999

J. Polym. Sci. A Polym. Chem.

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Selective single ring‐opening polymerization of spiroorthoesters with aluminium (III) acetylacetonate

Cited by 18 publications

References 9 publications

Reversible crosslinking-decrosslinking of polymers having bicyclo orthoester moieties in the side chains

Reversible crosslinking-decrosslinking of polymers having bicyclo orthoester moieties in the side chains

Cationic equilibrium ring‐opening polymerization of bicyclic monomers and its application to chemical recycling

Synthesis and cationic ring-opening polymerization of mono- and bifunctional spiro orthoesters containing ester groups and depolymerization of the obtained polymers: An approach to chemical recycling for polyesters as a model system

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