Polystyrene weight fractions

Both preparative and analytical GPC were employed to analyze a standard (NBS 706) polystyrene sample. Fractions were collected from the preparative column, the solvent was evaporated away, and the weight of each polymer fraction was obtained. The molecular weights of each fraction were obtained usmg an analytical gel permeation chromatograph calibrated in terms of both and M. The following data were obtained ... 

A curve showing the differential weight fraction versus chain length for the batch-prepared polystyrene is given in Figure 3. Figure 4 illustrates the exit age distributions obtained from the RTD experiments with benzene and with a 30 weight percent polymer solution. 

Figure 4 A Deborah number diagram for the polystyrene-ethylbenzene system showing the diffusion behavior as a function of weight fraction and temperature. (From Ref. 33.)...

Figure 12. Radius of poly(dimethyl slloxane) phase as a function of weight fraction In cross-poly(dimethyl slloxane)-Inter-cross-polystyrene sequential IPN s with three different crosslink densities of network I. Broken lines are theoretical values from...

Figure 8. Gel filtration of ethylated (/ -0-4)-(/ -/ )-DHP 16. Solid line Ethylated (/ -0-4)-(/ -/ )-DHP 16 after removal of low molecular weight fractions. The column was calibrated with (/ -0-4)-(/ -/ ) lignin substructure model trimer 6 (molecular weight 642) /3-0-4 lignin model dimer 1 (molecular weight 348) and polystyrenes of molecular weight 9000, 4000 (void), 2200 (indicated by A). Column Sephadex LH-20, 1.1 x 48 cm. Eluent DMF, 13.5-14.4 ml/hr. Detector Refractive index detector RI-2 (Japan Analytical Industry Co., Ltd.).

Like SEC/LALLS, the viscosity detector is sensitive to high molecular weight fractions as shown in Fig, 7. A shoulder at 3,000,000 molecular weight detected by the DRI becomes a peak when detected by the viscometer detector. The usefulness of the SEC/Viscometer method is exemplified by the study of branched polymers. Fig. 8 shows a log [ ] vs. log M plot for a randomly branched polystyrene obtained from the SEC/ iscometer technique. 

In the first example, a broad distribution sample of polystyrene was analyzed on a set of high efficiency Ultrastyragel GPC columns (lO. lO jlO A) with which It was determined that Mw = 214,000 and Mn = 87,000. In the Ideal case, a similar set of three (10, 10, lO A) preparative Styragel columns (each 57 mm I.D. X 4 ft) could have been used to fractionate the polystyrene sample. However, we Initially chose to demonstrate the extent of fractionation possible with only one preparative column and selected the lO A column packing material so as not to exclude any of the higher molecular weight fractions. 

The combined characterization results for all of the SAN samples (including the one polystyrene sample), i.e., weight fraction of AN mer units and [p] in... 

The radius of gyration of polymer coils can be determined independently from light scattering. Fox and Flory measured both Rg and [17] for various molecular weight fractions of polystyrene in various solvents at several temperatures. The following results were obtained ... 

Where w again represents weight fraction M is molecular weight and subscripts 1 and 2 refer to polymer and plasticizer, respectively. We use the notation, cp here to indicate that the constant may vary from one plasticizer to another. Figure 1 shows a plot of Tg vs. 1/ Mn for several polystyrene-plasticizer systems. If Mi is very much larger than M2, Equation 7 becomes... 

Figure 2. Glass transition temperature of polystyrene vs. weight fraction of chain...

Fig. 5.9. Comparison of extinction angle curves of high molecular weight fractions of polystyrene and cellulose tricarbanilate, using linear scales and reduced shear rate For data on polystyrene Taps. No. 5 and solvents see Table 3.2. (n) Taps. No. 5 in methyl (4-bromo-phenyl carbinol) at 18° C (theta-temperature), (V) the same at 50° C, (o) Taps. No. 5 in monobromo benzene at 25° C, ( ) cellulose tricarbanilate M = 720,000 in benzophenone at 55° C (jy = 4.70 cps) and (a) at...

Very recently, Gramain and Myard84 investigated the effect of the shear rate on LH, using high molecular weight fractions of polyacrylamide and polystyrene. Polyacrylamide was hydrolyzed to various degrees. Five commercial filters of pore radii from 1.5 to 6 fim were used as porous media. Measurements were carried out on polyacrylamide in water and polystyrene in toluene. 

Fig. 10. SANS from deuterated polystyrene (Mw = 1.95 x 106 g/mol) in dioctyl phthalate solution (3% polymer weight fraction). Experimental data (arbitrary units) and results of the fit to the inverse Zimm formula are plotted...

Fig. 11. SANS from deuterated polystyrene/polyfvinyl methyl ether) at equal compositions (50%/50% weight fractions). Experimental data fnmcro op.c cross, on nd fits to the de Gennes formula are plotted for four temperatures 60 C, 100 C, 110 C and 120 C (from bottom to...

Fig. 12. Flory-Huggins y/v0 parameters for deuterated polystyrene/poly(vinyl methyl ether) and protonated polystyrene/poly(vinyl methyl ether) interactions. The first one was obtained from binary (PSD/PVME) mixtures (50%/50% weight fraction) and the second one from ternary (PSD/PVME/PSH) blend mixtures (23.8%/25.6%/50.6%)...

FIG. 16.5 Glass transition temperature of solutions of Polystyrene in 12 different solvents as a function of the weight fraction of solvent, wv After Jenkel and Heusch (1953). Courtesy Hiithig and Wepf Verlag. 

Figure 19, which represents GPC curves of the polystyrene prepared in concentrated emulsions of various surfactant concentrations, shows that the amount of bulk phase decreases with increasing surfactant concentration. As the surfactant concentration increases, the weight fraction of polymer formed in the droplets of the gel increases first (Fig. 20) and then levels off, while the conversion shows a linear increase through the entire range of surfactant concentration. Obviously the stability of the gel cells depends on the surfactant concentration. The molecular weight of polymer produced in the gel phase... 

The Fracture Energy of Low Molecular Weight Fractions of Polystyrene... 

To illustrate the advantages of the technique, we apply it to narrow molecular weight fractions of low molecular weight polystyrene. 

The weight fraction activity coefficient of cyclohexane in polystyrene is found using Equation (3C-1). 

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