Step Copolymerization

Maréchal, Ernest; Fradet, Alain

doi:10.1016/b978-0-08-096701-1.00157-9

Cited by 4 publications

(5 citation statements)

References 47 publications

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“…Figure 8. Temperature dependence ß: (1) ethyl bromide; (2) allyl bromide; (3) (2-bromoethyl)benzene; (4) benzyl bromide;…”

Section: Resultsmentioning

confidence: 99%

Reaction kinetics of polymer substituents: macromolecular steric hindrance effect in quaternization of poly(vinylpyridines)

Frère¹,

Gramain²

1992

Macromolecules

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The retardation in the quaternization of poly(vinylpyridines) is of steric origin. Using very voluminous reagents, a steric effect also induces an important limitation to the extent of quaternization which is not included in theoretical treatments of neighboring group effects. A kinetic expression based on the classical second-order equation is proposed. It includes the rate constant feo for reaction of a pyridyl group and a macromolecular steric factor ß lowering the effective pyridine group concentration capable of reacting. ß characterizes the effect of the size and nature of the substituents on the accessibility of the pyridine groups. The expression describes very well the experimental kinetics published and associates to each alkylating agent a steric factor related to its bulkiness. Cessation of the reaction at a given temperature is predicted, in full agreement with experimental results. Possible reasons for such a limitation are discussed, and the change in the polymer conformation from a free-draining coil to a scarcely permeable globule is shown to account for the effect.

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“…Figure 8. Temperature dependence ß: (1) ethyl bromide; (2) allyl bromide; (3) (2-bromoethyl)benzene; (4) benzyl bromide;…”

Section: Resultsmentioning

confidence: 99%

Reaction kinetics of polymer substituents: macromolecular steric hindrance effect in quaternization of poly(vinylpyridines)

Frère¹,

Gramain²

1992

Macromolecules

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“…Many experimental studies have shown the influence of the polymer conformation and of the changes in conformation on the polymer reactivity. 2 Although the quaternization kinetics of P4VP have been extensively studied, the importance of this phenomena for this reaction has never been fully demonstrated. The results of the LS experiments clearly demonstrate the formation in sulfolane of dense and globular associations between the fully quaternized P4VP molecules while in methanol random free coils are observed.…”

Section: Discussionmentioning

confidence: 99%

“…The parameters influencingthereactivityinhomogeneousandpseudohomogeneous systems had already been described in detail by Sherrington 1 and Marechal. 2 A typical example of polymer chemical modification is the quaternization of poly(vinylpyridines) and more specially of poly(4-vinylpyridine) (P4VP). 3 At first, the quaternization rate follows second-order kinetics similar to the quaternization of pyridine; then, in the later stages, a retardation of the reaction is observed.…”

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confidence: 99%

Influence of the Conformation on Chemical Modification of Polymers: Study of the Quaternization of Poly(4-vinylpyridine)

Chovino

Gramain

1998

Macromolecules

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“…Copolycondensates have been approached from a theoretical point of view and Marechal and Fradet reviewed the field up to 1989. Vasnev and Kuchanov introduced a microheterogeneity index, K M , and they calculated its values as a function of the reactivity of the functional groups present in the reaction mixture.…”

Section: Introductionmentioning

confidence: 99%

Is It Possible to Extend the Coleman−Fox Method for Polymer Sequence Determination by NMR to Copolycondensates?

Montaudo¹

2004

J. Phys. Chem. B

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A new theory is presented for the interpretation of NMR spectra of copolycondensates, with special attention to those obtained by melt mixing of two macromolecular chains (reactive blending). The repeat unit is split into two parts, referred to as half-monomers. The present theory gives a highly accurate description of the changes in the sequence distribution during the reactive blending reaction, since the effect of the first and second neighbors along the macromolecular backbone (half-monomer penultimate effect) is explicitly considered. The theoretical predictions are compared with experimental data taken from the literature and, more specifically, NMR data concerning five copolymer systems, namely, a copolymer obtained by reactive blending of poly(ethylene terephthalate) and poly(ethylene adipate), an almost alternating copolymer with units of ether-sulfone and ether-ketone, a copolymer derived from 6-methyl-2,5-morpholinedione, and two copolymers obtained by reactive blending of poly(butylene terephthalate) with poly(bisphenolA carbonate) and Nylon6, respectively.

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Step Copolymerization

Cited by 4 publications

References 47 publications

Reaction kinetics of polymer substituents: macromolecular steric hindrance effect in quaternization of poly(vinylpyridines)

Reaction kinetics of polymer substituents: macromolecular steric hindrance effect in quaternization of poly(vinylpyridines)

Influence of the Conformation on Chemical Modification of Polymers: Study of the Quaternization of Poly(4-vinylpyridine)

Is It Possible to Extend the Coleman−Fox Method for Polymer Sequence Determination by NMR to Copolycondensates?

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