Polystyrene light scattering measurements

K and a in the expression, [17] = KM , are 3.7 x 10-5 m3 kg-1 and 0.62, respectively, for this polymer-solvent system. Assuming a constant density for the solutions, calculate an average relative molecular mass for the polystyrene sample. How would this relative molecular mass be expected to compare with the relative molecular mass of the same sample of polystyrene in toluene determined from a) osmotic pressure and (b) light-scattering measurements ... 

Molecular weights were based on polystyrene standards. Vapor pressure osmometry and light-scattering measurements indicate that the true molecular weights are approximately 2 times larger. 

There continues to be extensive interest in latexes and micellar systems. The structure of acrylic latex particles has been investigated by non-radiative energy transfer by labelling the co-monomers with fluorescent acceptor-donor systems. Phase separations could also be measured in this way. Excimer fluorescence has been used to measure the critical micelle temperature in diblock copolymers of polystyrene with ethylene-propylene and the results agree well with dynamic light scattering measurements. Fluorescence anisotropy has been used to measure adsorption isotherms of labelled polymers to silica as well as segmental relaxation processes in solutions of acrylic polymers. In the latter case unusual interactions were indicated between the polymers and chlorinated hydrocarbon solvents. Fluorescence analysis of hydrophobically modifled cellulose have shown the operation of slow dynamic processes while fluorescence... 

From these data determine the second virial coefficient and the theta temperature of poly(a-methyl styrene) in cyclohexane, knowing that K = K hl AhlAcf, where K = 18.17 mol cm , the refractive index increment (d /dc) is 0.199 ml gr, and the temperature dependence of the refractive index is expressed by = -0.0005327 x T (°C) + 1.446. Static light-scattering measurements were carried out by Zimm (1948b) on polystyrene in butanone at 340 K at two concentrations. 

MCD McDonald, C.J. and Claesson, S., Light scattering measurements under high pressure. I. Pure solvents and polystyrene in methyl isobutyl ketone, Chem. Scripta, 4, 155, 1973. 

Because of the significant implication of Scholte s work Einaga and coworkers considered it worthwhile to repeat similar experiments with care. Thus, they carried out light scattering measurements first on polystyrene in cyclohexane [17] and then on poly(isoprene) in dioxane. They obtained essentially similar results for the two systems. Here, the data for polystyrene in cyclohexmie are illustrated. 

T. Kato, K. N amura, M. Kawaguchi, and A. Takahashi. Quasielastic light scattering measurements of polystyrene latices and conformation of poly(oxyethylene) adsorbed on the latices. Polymer J. 13 1037-1043 (1981). 

Kusters et al. [22] analysed polystyrene latex particles of about 1 p,m diameter aggregated in salt solution in a stirred tank, with samples withdrawn from the tank by pipette for light-scattering measurements. They found mass fractal dimensions of around 2.5 using the volume obscuration method. 

Lodge, Markland, and Wheeler [112] used QELSS to measure Dp of 3-armed and 12-axmed star polystyrenes in polyvinylmethylether orthofluorotoluene. The 3-armed stars had P of 379 and 1190 kDa the 12-armed stars had P of 55, 467, 1110, and 1690 kDa. Polyvinylmethyl ethers used as matrices had M of 140, 630, aud 1300 kDa. Polystyrenes all had Mp,/M < 1.1 the PVMEs had M /Mn 1.6. Light scattering measurements were made of Rg of linear, 3-axm and 12-arm stars with > IMDa in solutions of 250 kDa PVME for c < 50 g/L. Lodge, et al. [112] numerically modified their reported Dp, as described by Wheeler and Lodge [125] this modification factor has been removed here to recover the measured diffusion coefficients.. For every P M combination, a stretched exponential describes Ds c) well. 

A homologous series of commercially available sodium-polystyrene sulfonate samples were characterized by viscometry and light scattering measurements. The molecular parameters were determined and the degree of sulfo-... 

Figure 4.16. Scaling plot for the correlation length evaluated in static light-scattering measurements for solutions of polystyrene in toluene and methyl ethyl ketone. The reduced correlation length i/Rgo is plotted as a function of l6/9)A2Mc in a double logarithmic scale. The dashed line has a slope of —3/4. (From Ref. 48.)...

Light-scattering measurements at 436 nm of a polystyrene-poly(methyl methacrylate) copolymer in the three different solvents give the following data ... 

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