PBA–PMMA 3‐Arm Star Block Copolymer Thermoplastic Elastomers

Dufour, Bruno; Koynov, Kaloian; Pakuła, Tadeusz; Matyjaszewski, Krzysztof

doi:10.1002/macp.200800151

Cited by 54 publications

(43 citation statements)

References 94 publications

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“…The rate of activation of a bromo-terminated PDMAEMA chain end is faster than the activation of a 2-bromoisobutyrate β-CD chain ends (ω-functional arms) [55,56]. Typically, halogen exchange procedures [55][56][57][58] are employed to solve this problem, but it can't be used for systems with low concentrations of catalyst, because of poor initiation efficiency.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of cationic star polymers by simplified electrochemically mediated ATRP

Chmielarz¹

2016

Express Polym. Lett.

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Abstract. Cyclodextrin-based cationic star polymers were synthesized using β-cyclodextrin (β-CD) core, and 2-(dimethylamino)ethyl methacrylate (DMAEMA) as hydrophilic arms. Star-shaped polymers were prepared via a simplified electrochemically mediated ATRP (seATRP) under potentiostatic and galvanostatic conditions. The polymerization results showed molecular weight (MW) evolution close to theoretical values, and maintained narrow molecular weight distribution (MWD) of obtained stars. The rate of the polymerizations was controlled by applying more positive potential values thereby suppressing star-star coupling reactions. Successful chain extension of the ω-functional arms with a hydrophobic n-butyl acrylate (BA) formed star block copolymers and confirmed the living nature of the β-CD-PDMAEMA star polymers prepared by seATRP. Novelty of this work is that the β-CD-PDMAEMA-b-PBA cationic star block copolymers were synthesized for the first time via seATRP procedure, utilizing only 40 ppm of catalyst complex. The results from 1 H NMR spectral studies support the formation of cationic star (co)polymers.

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Section: Resultsmentioning

confidence: 99%

Synthesis of cationic star polymers by simplified electrochemically mediated ATRP

Chmielarz¹

2016

Express Polym. Lett.

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“…In ATRP, the block order can be altered by using halogen exchange (as discussed before). This way, thermoplastic elastomers of PMMA-PBA-PMMA were successfully obtained by starting from Br-PBA-Br and using CuCl/L to chain extend with MMA [101,102,104,272]. ABC, ABCD, and ABCBA blocks were also prepared by ATRP [273].…”

Section: Block Copolymers By a Single Crp Methodsmentioning

confidence: 99%

“…This effectively leads to increased initiation efficiency from the added macroinitiator and preparation of a second block with lower polydispersity. In this way, block copolymers were successfully prepared from poly(n-butyl acrylate) and extended with polyacrylonitrile or PMMA [104,105].…”

Section: Monomersmentioning

confidence: 99%

Radical Polymerization

Matyjaszewski

2009

Controlled and Living Polymerizations

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Approximately 50% of all synthetic polymers are currently made via radical polymerization (RP) processes. The commercial success of RP can be attributed to the large range of radically polymerizable monomers, their facile copolymerization, the convenient reaction conditions employed (typically room temperature to 100 • C, ambient pressure), and very minimal requirements for purification of monomers and solvents. RP is not affected by water and protic impurities and can be carried out in bulk, solution, aqueous suspension, emulsion, dispersion, etc. The range of monomers is larger for RP than for any other chain polymerization because radicals are tolerant to many functionalities, including acidic, hydroxy, and amino groups. In conventional RP, high molecular weight (MW) polymers are formed at the early stages of the polymerization, and neither long reaction times nor high conversions are required, in sharp contrast to step-growth polymerization.However, RP has some limitations, especially in comparison with ionic processes that provide facile routes to living polymers. For a polymerization to be considered ''living,'' the contribution of chain breaking reactions such as termination and transfer should be negligible. While transfer is not a major issue in RP when the appropriate conditions are applied, termination is much less avoidable and is a major limitation of RP. In contrast to ionic reactions, in which cations or anions do not react via bimolecular termination, radicals terminate with a diffusion controlled rate. To form high MW polymers, the relative probability of such termination must be minimized. This is accomplished by running RP at very low concentrations (from ppb to ppm) of propagating radicals. The concentrations of growing species are thus much lower in RP than in carbanionic or ring-opening polymerizations. In RP, a steady concentration of radicals is established by balancing the rate of termination with that of initiation. The rate of propagation is much faster than the rate of initiation/termination (as required to keep radical concentration low). Therefore, Controlled and Living Polymerizations. Edited a Measurements in bulk at 40 • C and ambient pressure, unless otherwise stated. b k t reported at 1000 bar. c Solvent = chlorobenzene. E p and A p represent the Arrhenius activation energy for propagation and frequency factor for propagation, respectively. Typical Features of Radical Polymerization 107coefficients of termination depend on chain length and conversion (viscosity), the values in Table 3.1 are given for low conversion and DP ≈ 100. CopolymerizationFacile statistical copolymerization is one of the main advantages of RP. In contrast to ionic polymerization, the reactivities of many monomers are relatively similar, which makes them easy to copolymerize statistically. For monomers with opposite polarities, there is a tendency for alternation (r A r B < 1, where r A = k AA /k AB and r B = k BB /k BA ). Electrophilic radicals (i.e., those with -CN, -C(O)OR, or Cl groups) prefer to react ...

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“…Most commercial TPEs such as polystyrene‐ b ‐polybutadiene‐ b ‐polystyrene (SBS) and polystyrene‐ b ‐polyisoprene‐ b ‐polystyrene (SIS) triblock copolymers are prepared via ionic polymerization, which is known for its stringent conditions such as sensitivity to air, water, impurities, low polymerization temperature, and poor tolerance to functionalities and polarities, although recent controlled radical polymerizations, including reversible addition–fragmentation chain transfer (RAFT) polymerization, could achieve limited success in preparing these ABA triblock copolymers . There are a few other architectures designed for TPEs, including star block copolymers and multigraft copolymers . From the view of sustainability, a simple and economical approach is more favorable.…”

Section: Introductionmentioning

confidence: 99%

UV‐Absorbent Lignin‐Based Multi‐Arm Star Thermoplastic Elastomers

Yu¹,

Wang²,

Wang³

et al. 2014

Macromol. Rapid Commun.

103

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Lignin-grafted copolymers, namely lignin-graft-poly(methyl methacrylate-co-butyl acrylate) (lignin-g-P(MMA-co-BA)), are synthesized via "grafting from" atom transfer radical polymerization (ATRP) with the aid of lignin-based macroinitiators. By manipulating the monomer feed ratios of MMA/BA, grafted copolymers with tunable glass transition temperatures (-10-40 °C) are obtained. These copolymers are evaluated as sustainable thermoplastic elastomers (TPEs). The results suggest that the mechanical properties of these TPEs lignin-g-P(MMA-co-BA) copolymers are improved significantly by comparing with those of linear P(MMA-co-BA) copolymer counterparts, and the elastic strain recovery is nearly 70%. Lignin-g-P(MMA-co-BA) copolymers exhibit high absorption in the range of the UV spectrum, which might allow for applications in UV-blocking coatings.

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PBA–PMMA 3‐Arm Star Block Copolymer Thermoplastic Elastomers

Cited by 54 publications

References 94 publications

Synthesis of cationic star polymers by simplified electrochemically mediated ATRP

Synthesis of cationic star polymers by simplified electrochemically mediated ATRP

Radical Polymerization

UV‐Absorbent Lignin‐Based Multi‐Arm Star Thermoplastic Elastomers

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