Starpolymers by soft‐hard‐soft block copolymers

Kéki, Sándor; Bogács, Cs.; Bogács, L.; Daróczi, Lajos; Zsuga, Miklós

doi:10.1002/apmc.1997.052450116

“…In particular, telechelic poly(IB) with exo-olefin terminals, [80][81][82][83] which is useful as a reactive polyisobutylene for industrial applications, can be prepared without any subsequent modification reactions if an appropriate bifunctional RAFT agent with two exoolefins is used. The bifunctional RAFT agent (11) (Figure S11) was thus synthesized from 1,4-bis(2-chloro-2propyl)benzene (p-dicumylchloride) [83][84][85] and α-phenyl trimethylsilyl enol ether followed by the Wittig reaction, which is similar to the procedure used for the syntheses of the "heterodimers" described above.…”

Section: Methodsmentioning

confidence: 99%

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

Tanimoto,

Uchiyama,

Kamigaito

2023

Angew Chem Int Ed

1

0

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A series of exo‐olefin compounds ((CH3)2C(PhY)–CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α‐methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p‐toluenesulfonic acid (TsOH) via β‐C–H scision. They were subsequently used as reversible chain transfer agents for sulfur‐free cationic RAFT polymerization of αMS via β‐C–C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo‐olefin compounds with electron‐donating substituents, such as a 4‐MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo‐olefin terminals. Other exo‐olefin compounds (R–CH2C(=CH2)(4‐MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur‐free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo‐olefin αMS dimer ((CH3)2C(Ph)–CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo‐olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo‐olefins. Finally, block copolymers of αMS and MMA were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo‐olefin terminals containing 4‐MeOPh groups as common sulfur‐free RAFT groups for both cationic and radical polymerizations.

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“…Combining high T g (hard) blocks with low T g (soft) blocks should lead to a nanoscale, 3D network of hard and soft domains when phase separated. Such materials are desirable for self-healing, 28 and shapememory polymer applications, 29 and are often used as additives to improve properties such as viscosity, 30 and impact strength. 31 ABA triblock copolymers, where A is a hard block and B is a soft block, have found uses as thermoplastic elastomers (TPEs) 32 and pressure sensitive adhesives (PSAs), 33 depending on their material properties.…”

Section: Introductionmentioning

confidence: 99%

RAFT polymerisation of renewable terpene (meth)acrylates and the convergent synthesis of methacrylate–acrylate–methacrylate triblock copolymers

Atkinson

¹

,

Monaghan

²

,

Elsmore

³

et al. 2021

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Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

Tanimoto

¹

,

Uchiyama

²

,

Kamigaito

³

2023

Angewandte Chemie

0

View full text Add to dashboard Cite

A series of exo‐olefin compounds ((CH3)2C(PhY)–CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α‐methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p‐toluenesulfonic acid (TsOH) via β‐C–H scision. They were subsequently used as reversible chain transfer agents for sulfur‐free cationic RAFT polymerization of αMS via β‐C–C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo‐olefin compounds with electron‐donating substituents, such as a 4‐MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo‐olefin terminals. Other exo‐olefin compounds (R–CH2C(=CH2)(4‐MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur‐free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo‐olefin αMS dimer ((CH3)2C(Ph)–CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo‐olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo‐olefins. Finally, block copolymers of αMS and MMA were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo‐olefin terminals containing 4‐MeOPh groups as common sulfur‐free RAFT groups for both cationic and radical polymerizations.

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Starpolymers by soft‐hard‐soft block copolymers

Cited by 4 publications

References 10 publications

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

RAFT polymerisation of renewable terpene (meth)acrylates and the convergent synthesis of methacrylate–acrylate–methacrylate triblock copolymers

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

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