Dilute solution properties of narrow-distribution polystyrene

Papazian, L. A.

doi:10.1016/0032-3861(69)90051-2

Cited by 37 publications

(15 citation statements)

References 64 publications

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“…When we approach the 0 temperature of the solvent N , tends to infinity (the chain consists of one only blob as predicted by thermal blob theory). Plotting log[v] versus logM (MHS representation) for many polymer-solvent systems we observe, as has already been pointed out by different authors, that the power law between [17] and Mbegins above a certain molecular weight M,. Below M , we observe a crossover region in which the exponent a continuously decreases.…”

Section: Determination Of the Number Of Statistical Segments Making Usupporting

confidence: 74%

Characterization of polymers based on quantitative aspects of blob theory

Dondos

1994

Acta Polymerica

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Using an equation derived from blob theory we calculate the number of statistical segments of which one blob consists (N,).The same characteristic number can also be directly determined from the Mark-Houwink-Sakurada (MHS) representation. The above characteristic number depends only on the quality (i.e., properties) of the solvent and is found to be the same for different polymers if these polymers are dissolved in solvents forwhich the exponent in the MHS equation is the same. Based on the above determination of N,, we calculate the adjustable parameter na of thermal blob theory. The obtained value lies near a mean value of 10. Knowing the 0 temperature for a number of polymer-solvent systems, we propose a relation giving the 0 temperature as a function of the rigidity of the polymers and the properties of the solvents. Combining relations derived either from the two-parameter theory or from blob theory, we propose relations that give the adjustable parameter Crelating the number of blobs of a chain to its excluded-volume parameter z. Knowing the adjustable parameter C(mean value 36) and using a relation derived also from the combination ofthe two-parameter theory with blob theory, we obtain the long range interaction parameter B of any polymer-solvent system. The obtained values are almost the same as the values obtaiend directly from the Stockmayer-Fixman-Burchard representation. a PP, polypropylene; POE, poly(ethy1ene oxide); PIB, polyisobutylene; PMMA, poly(methylmethacry1ate); PS, polystyrene; P(p-tert-b-S), polyb-tert-butylstyrene); P(mmS), poly(m-methylstyrene): P(2,4-d-mS), poly(2,4-dimethylstyrene); P(2,4,6-tmS), poly(2,4,6-trimethylstyrene); P(2-eth-but-M), poly(2-ethyl butyl methacrylate); PZVP, poly(2-vinyl pyridine); PDPP, poly(2,6-diisopropylphenyl methacrylate).': A in cm. * Our results.K , in ml g-"2 mo1"2. B and B S F B in ml.Acta Polymer., 45, 355-360 (1994) Quantitative aspects of blob theory

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Section: Determination Of the Number Of Statistical Segments Making Usupporting

confidence: 74%

Characterization of polymers based on quantitative aspects of blob theory

Dondos

1994

Acta Polymerica

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“…For the Huggins coefficient, the usual value in a good solvent, 43,44 k H ϭ0.35, was adopted; no molecular-weight dependence has been reported in the literature for k H .…”

Section: ϫ3mentioning

confidence: 99%

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

Zhang

Sengers

et al. 2000

The Journal of Chemical Physics

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Effects of viscoelasticity of bulk polymer solution on the surface modes as probed by laser light scattering J. Chem. Phys. 109, 6103 (1998) We have performed light-scattering measurements in dilute and semidilute polymer solutions of polystyrene in toluene when subjected to stationary temperature gradients. Five solutions with concentrations below and one solution with a concentration above the overlap concentration were investigated. The experiments confirm the presence of long-range nonequilibrium concentration fluctuations which are proportional to (ٌT) 2 /k 4 , where ٌT is the applied temperature gradient and k is the wave number of the fluctuations. In addition, we demonstrate that the strength of the nonequilibrium concentration fluctuations, observed in the dilute and semidilute solution regime, agrees with theoretical values calculated from fluctuating hydrodynamics. Further theoretical and experimental work will be needed to understand nonequilibrium fluctuations in polymer solutions at higher concentrations.

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“…The intrinsic viscosity of polymers was determined using a Ubbelohde viscometer at 24 ± 0.1°C, and THF as the solvent. The molar masses of polymer M v can be calculated from the intrinsic viscosity 16…”

Section: Methodsmentioning

confidence: 99%

Ultrasonically irradiated emulsion polymerization of styrene in the presence of a polymeric surfactant

Zhang

Cao

2004

J of Applied Polymer Sci

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A polymeric surfactant based on carboxymethyl cellulose and alkyl poly(etheroxy) acrylate (CMC-A9) was used in ultrasonically irradiated emulsion polymerization of styrene. Polystyrene nanoparticles (30 -60 nm) with high molecular weight were prepared. Compared with the conventional emulsion polymerization, the introduction of CMC-A9 in the polymerization yielded higher monomer conversion in a shorter time and under lower ultrasonic power output. A single latex particle contained only a few polymer chains with average chain numbers of 2-19. The particle size and polymer chain per particle could be controlled by changing the concentration of CMC-A9 and SDS.The effect of CMC-A9 and SDS on ultrasonically irradiated emulsion polymerization kinetics was studied. The results indicated that the ultrasonically irradiated emulsion polymerization had a similar nucleation mechanism to a miniemulsion polymerization system. This is attributed to the high ratio of radicals and a great number of smaller sizes of monomer droplets produced under ultrasonic irradiation.

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Dilute solution properties of narrow-distribution polystyrene

Cited by 37 publications

References 64 publications

Characterization of polymers based on quantitative aspects of blob theory

Characterization of polymers based on quantitative aspects of blob theory

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

Ultrasonically irradiated emulsion polymerization of styrene in the presence of a polymeric surfactant

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