The effect of monomer preferential solvation in radical copolymerization: Reactivity ratios and compositional distribution
| Autor: | Yu.D. Semchikov, L. A. Smirnova, V. V. Izvolenskii, N. A. Kopylova |
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| Rok vydání: | 1996 |
| Předmět: |
chemistry.chemical_classification
Polymers and Plastics Chemistry Organic Chemistry Intermolecular force Solvation General Physics and Astronomy Polymer Methacrylate chemistry.chemical_compound Monomer Polymer chemistry Pyridine Materials Chemistry Copolymer Physical chemistry Reactivity (chemistry) |
| Zdroj: | European Polymer Journal. 32:1213-1219 |
| ISSN: | 0014-3057 |
| DOI: | 10.1016/s0014-3057(96)00054-7 |
| Popis: | The effects of preferential solvation of monomers by polymer coils in homogeneous radical copolymerization at low conversion (5–7%) have been studied for styrene-acrylonitrile, styrenemethacrylic acid, styrene-acrylamide, styrene-acrylic acid, styrene-butyl methacrylate, vinyl acetate-2-methyl-5-vinyl-pyridine and vinyl acetate-2-vinyl pyridine. In the simplest cases, the copolymer composition and microstructure can be described by the Mayo-Lewis model with the apparent or effective monomer reactivity ratios: r 2 = r 2 0 γ, r 1 = r 1 0 γ , where r 1 0 , r 2 0 are ideal reactivity ratios defined by the monomer structure, γ is the monomer distribution coefficient. The most fundamental effect of preferential solvation is the relation between the copolymer composition and molecular weight caused by the dependence of preferential solvation coefficient γ upon the length of a growing chain. This dependence leads to two previously unknown types of chemical heterogeneity of low-conversion copolymers, viz. intra- and intermolecular gradient chemical heterogeneity. |
| Databáze: | OpenAIRE |
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