31 research outputs found

    Processing of polymers using reactive solvents

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    A review with many refs. on processing of polymers using reactive solvents including classification of synthetic polymers, guidelines for the selection of reactive solvents, basic aspects of processing, examples of intractable and tractable polymer/reactive solvent syste

    Thermodynamics of swelling of latex particles with two monomers

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    The partitioning of 2 monomers between the latex particle, monomer droplet, and aq. phases of an emulsion polymer latex are measured at satn. swelling of the latex particle phase (corresponding to intervals I and II of an emulsion polymn.). The monomer (Me acrylate, Bu acrylate, styrene) and polymer of these expts. correspond well to a simplified thermodn. theory of the satn. swelling of an emulsion polymer with 2 monomers, in which it is realized that the fraction of 1 monomer is equiv. in the latex particle and monomer droplet phases. Henry's law holds for monomers, both in the absence and in the presence of swollen latex particles. A simple empirical relation is developed whereby the concn. of 2 monomers at any ratio can be calcd. from the individual satn. concn. of the 2 monomers in the latex of interes

    Partial swelling of latex particles with monomers

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    Two methods are described for exptl. detg. the concns. of monomer in both the aq. phase and the latex particle phase during partial swelling of latex particles, and therefore also during interval III of an emulsion polymn. The ratio of the monomer concns. in the aq. phase, both below and at satn., can be related to the vol. fraction of polymer in the latex particles via the Vanzo equation. Comparison of theory and expts. for the Me acrylate and Me acrylate-styrene copolymer systems shows that the monomer partitioning is insensitive to temp., latex particle radius, polymer compn., polymer mol. wt., and polymer crosslinking. Thermodn. treatment of these and previously published partitioning results shows, at high vol. fractions of polymer, that the conformational entropy of mixing of monomer and polymer is the significant term detg. the degree of partial latex particle swelling by monomer. Theor. predictions of exptl. results are quite insensitive to values of the Flory-Huggins interaction parameter and to the latex particle-water interfacial tension. A simple model is developed for the estn. of monomer partitioning which requires only the satn. monomer concns. in the particle and aq. phase

    Some outstanding problems concerning heterogeneous polymerizations in aqueous media : thermodynamics, kinetics and modeling

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    Swelling of phospholipid bilayers by solvents

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