Block and graft polymers their synthesis, especially by living polymer technique, and their properties

Szwarc, M.

doi:10.1002/pen.760130102

Cited by 31 publications

(7 citation statements)

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“…Sequential monomer addition, mechanistic transformation, and segment coupling approaches are the most common methods for the syntheses of well‐defined block copolymers. In sequential monomer addition approach, after the first monomer is consumed, another monomer is added to the reaction medium, and obtained block copolymer is isolated by precipitation . The major drawback of this approach is that it is limited to monomers, which can only polymerize with the same mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…In sequential monomer addition approach, after the first monomer is consumed, another monomer is added to the reaction medium, and obtained block copolymer is isolated by precipitation. 22 The major drawback of this approach is that it is limited to monomers, which can only polymerize with the same mechanism. In the mechanistic transformation approach, one of the segments is synthesized by one polymerization mode and the other segment(s) by another mode.…”

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confidence: 99%

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A versatile approach for the preparation of end‐functional polymers and block copolymers by stable radical exchange reactions

Göksu

Yılmaz

Yaǧcı

2019

J. Polym. Sci. Part A: Polym. Chem.

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A versatile strategy for the preparation of end‐functional polymers and block copolymers by radical exchange reactions is described. For this purpose, first polystyrene with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl end group (PS‐TEMPO) is prepared by nitroxide‐mediated radical polymerization (NMRP). In the subsequent step, these polymers are heated to 130 °C in the presence of independently prepared TEMPO derivatives bearing hydroxyl, azide and carboxylic acid functionalities, and polymers such as poly(ethylene glycol) (TEMPO‐PEG) and poly(ε‐caprolactone) (TEMPO‐PCL). Due to the simultaneous radical generation and reversible termination of the polymer radical, TEMPO moiety on polystyrene is replaced to form the corresponding end‐functional polymers and block copolymers. The intermediates and final polymers are characterized by 1H NMR, UV, IR, and GPC measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2387–2395

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

A versatile approach for the preparation of end‐functional polymers and block copolymers by stable radical exchange reactions

Göksu

Yılmaz

Yaǧcı

2019

J. Polym. Sci. Part A: Polym. Chem.

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“…Side reactions which had been proposed in the polymerization of glutamate NCA are vcry unlil\rcly for the present NCA. 22 The activated-monomer type polymerization lrading to a high molecular weight and a broad distribution is impossible for the present SCA, which is an imino acid XCA.22 So, thr number-averagr degree of polymerization (n) of poly(N-methyl-L-alanine) is calculatedz3 according to Ey. (1).…”

Section: Introductionmentioning

confidence: 98%

Polymerization of Ring-Substituted Phenylalanine N-Carboxyanhydride by Poly(2-vinylpyridine)

Imanishi

Amimoto

Hashimoto

et al. 1976

Polym J

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ABSTRACT:Polymerizations of a series of phenylalanine NCA's carrying various ring substituents, such as p- CHsO,, and m-N02, initiated by poly(2-vinylpyridine) were investigated in different solvents, such as dimethylformamide, nitrobenzene, methyl benzoate, and acetophenone; the polymerization rates were compared with those induced by a-picoline. The binding constants of the a-amino acid NCA's for different initiators were also determined. It was concluded that in methyl benzoate or acetophenone poly(2-vinylpyridine) is particularly effective in the polymerization of electron-accepting NCA because the electron-donating polymer binds NCA through hydrogen bonding as well as through a charge-transfer interaction. In nitrobenzene only the hydrogen bonding between the polymer and the NCA's was involved in the accelerated polymerization by poly(2-vinylpyridine). In dimethylformamide no interactions were operating between the polymer and the NCA's, and consequently the polymerization by poly(2-vinylpyridine) which is a weaker base than a-picoline was slower. These findings suggest the possibility of substrate-selective polymerization using a polymer initiator with a suitable choice of solvent.KEY WORDS Ring-Substituted Phenylalanine NCA / Polymer Initiator / Solvent / Hydrogen Bond / Charge-Transfer Interaction / Selectivity / The efficiency and the specificity of enzyme catalysis have been considered to come partly from the complexation of a substrate by the enzyme. 1 The complexation takes place through secondary valence forces such as hydrogen bonding, charge-transfer interaction, hydrophobic interaction, and electrostatic interaction. 2 In order to transplant features of the enzyme into a synthetic catalyst, the enzyme catalysis has been investigated by using simplified model systems. 3 These models have usually been macromolecular compounds, which possess sites for substrate binding as well as sites for catalytic action. The present authors have investigated the polymerization of a-amino acid N-carboxyanhydride (NCA) initiated by polymeric amines. The binding of NCA by the polymeric amine through the hydrogen bonding resulted in a sizable increase of the polymerization rate. 4 -7 The charge-transfer interaction between the polymeric amine and NCA was also found to affect the polymerization rate. 8 Furthermore, it has been suggested that the hydrogen bonding and the charge-transfer interaction affect the polymerization rate concurrently. 9 A combination of different types of interactions, such as hydrogen bonding and charge-transfer interaction, could lead to a more efficient and more selective catalyst, as in the case of enzymes. To this end poly(2-vinylpyridine) was chosen as an initiator for the NCA polymerization. The pyridyl group, a tertiary amine which initiates the polymerization of NCA, 10 is a hydrogen-bond acceptor and an electron donor. Therefore poly(2-vinylpyridine) could be an efficient and selective initiator for the polymerization of NCA, which carries an active hydrogen and an electron-accepti...

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“…In the alkyllithium-initiated polymerizations of vinyl monomers, Lewis bases such as ethers and amines alter the kinetics, stereochemistry, and monomer reactivity ratios for copolymerization. [1][2][3][4] In general, the magnitude of these effects has been directly or indirectly attributed to the extent or nature of the interaction of the Lewis base with the organolithium chain end of the growing polymer. Some insight into the molecular basis for these effects has been provided by a variety of NMR, colligative property, and light-scattering measurements of simple and polymeric organolithium compounds in hydrocarbon and basic solvents.…”

Section: Introductionmentioning

confidence: 99%

Solvation of polymeric organolithium compounds. Heats of interaction of tetrahydrofurans and N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly(butadienyl)lithium

Quirk

McFay

1986

J. Polym. Sci. A Polym. Chem.

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The enthalpies of interaction of tetrahydrofuran, 2,5‐dimethyltetrahydrofuran and N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with 0.02M benzene solutions of poly(butadienyl)lithium (MN∼4,000) were measured as a function of R([base]/[Li]) using highdilution, solution calorimetry at 25°C. At low R values (ca. 0.2) the enthalpy of interaction of THF ( — 6.1 kcal/mol) is only 1.5 kcal/mol more exothermic than with 2,5‐dimethyltetrahydrofuran and both decrease rapidly with increasing R value. These results indicate that this coordination process is much less sensitive to the steric requirements of the base than analogous processes for poly(isoprenyl)lithium and poly(styryl)lithium. The concentration dependence for the enthalpy of interaction with TMEDA falls off precipitously with increasing R values from an initial value of −12.4 kcal/mol at R = 0.14. These results suggest either a higher degree of association or a less favorable dissociation equilibrium constant for poly(butadienyl)lithium versus poly(isoprenyl)lithium.

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Block and graft polymers their synthesis, especially by living polymer technique, and their properties

Cited by 31 publications

References 40 publications

A versatile approach for the preparation of end‐functional polymers and block copolymers by stable radical exchange reactions

A versatile approach for the preparation of end‐functional polymers and block copolymers by stable radical exchange reactions

Polymerization of Ring-Substituted Phenylalanine N-Carboxyanhydride by Poly(2-vinylpyridine)

Solvation of polymeric organolithium compounds. Heats of interaction of tetrahydrofurans and N,N,N′,N′‐tetramethylethylenediamine (TMEDA) with poly(butadienyl)lithium

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