Polystyrene solutions

Plot the scaling behavior for the surface tension of polystyrene solutions using Eq. III-64, for N = 1,000 and T from zero to Tc- Now plot the behavior for T = 0.87 for N = 100-1000. Comment on the influence of polymers on surface tension. 

Various amounts of either ethanol or hexane were added to polystyrene solutions in benzene and r was measured for several concentrations of polymer. The following results were obtainedf (c2 in g liter" Hca/r in mol g M ... 

Low Conversion Reactors. The major problem in temperature control in low conversion reactors is the orders cf magnitude increase in viscosity as the conversion increases. Fig.8 shows the viscosity of a polystyrene solution as the function of percent PS. The data are for polystyrene with a Staudinger molecular weight of 60,000 at 100 C and 150 C in a cumene solution, a satisfactory analog for styrene monomer solutions. As the polymer concentration increases from 0 to 60%, viscosity increases from about 1 cp to 10 cp. 

Ide and White W studied the viscoelastic effects in agitating polystyrene solutions with a turbine. At concentrations below 50% PS, flow was normal. Abovfe 35%, the viscoelastic forces caused the flow to reverse, moving away from the impeller along the axis. At 30 to 35% PS, both occurred, causing a segregated secondary flow around the turbine. 

Figure 8, Viscosity of polystyrene solutions (Mst = 60,000) (5) and recommended ranges of different agitators (9,10)...

To illustrate the application of corresponding-states theory to polymer solution calculations, we consider two cases of sol-vent/polymer vapor-liquid equilibria. The first case we consider is that of the chloroform/polystyrene solution. The second is that of benzene/polyethylene oxide. 

The chloroform/polystyrene solution exhibits highly nonideal behavior. As shown by curve C in Figure 4, the x parameter for this solution rises from a low value to a high value as solvent concentration increases. However, as shown in Figure 5, the partial pressure of chloroform above a mixture of... 

Figure 11.2 (a) Microscope image of Benard from Ref 33). (b) Two microscope snapshots convection cells (indicated by the circle in the of an evaporating polystyrene solution on silicon upper left corner) and tears ofwine (indicated wafer. The time between the two frames is by the white arrows) in an evaporating approximately 100 ms. The polymer droplets... 

For concentrated polystyrene solutions (c>c ) in n-butylbenzene, Graessley and co-workers [36] observed that the shift factor hconc depends on the number of entanglements per macromolecule E. 

Fig Reduced Osmotic pressure of polystyrene solutions in mixed-solvents as a function of the concentration. 

The solution is transformed to an oil-in-oil emulsion in which a polystyrene solution forms the disperse phase and the elastomer polyester component solution the continuous phase. The point of phase separation is observed experimentally by the onset of turbidity, due to the Tyndall effect. The conversion required for phase separation to occur depends basically on the solubility of the polystyrene chains in the elastomer solution, which in turn is governed by the elastomer concentration and compatibility of the two polymers. 

Zimm, B.H. 1948. Apparatus and methods for measurement and interpretation of the angular variation of light scattering Preliminary results on polystyrene solutions. J. Chem. Phys., 37 19. 

Recently, by using improved nanosecond pulse radiolysis with the monitoring wavelength region from 300 to 1600 nm [44], absorption spectra due to main reactive intermediates such as the intramolecular dimer cation radical in the near-IR wavelength region were clearly observed in the pulse radiolysis of polystyrene in various solutions [47]. For example. Fig. 1 shows the absorption spectra observed in the pulse radiolysis of polystyrene solutions in CH2CI2. 

Figure 1 Transient absorption spectra obtained in the pulse radiolysis in 200 mM (base mM unit) polystyrene solutions in CH2CI2 at the pulse end ( ) and 100 nsec after the pulse (A). Inset time-dependent behavior observed at 1200 nm.

The sensitized photo-Fries rearrangement of 55 in benzene, toluene, and in concentrated polystyrene solution in dioxane is effectively quenched with biacetyl.4 This phenomenon must again be attributed to quenching of the aromatic energy donor, because in pure dioxane the photorearrangement of 55 is not influenced by biacetyl (vide supra). 

Using a 5-ml volumetric pipette, add 5 ml of the filtered stock polystyrene) solution to the solvent in bulb A. 

The polymer should be dissolved at room temperature [28]. Magnetic stirring devices or laboratory shakers are recommended to aid dissolution. Excessive temperature or ultrasonic devices may cause the polymer to degrade. Polystyrene solutions prepared with solvents such as THF are very stable, as long as MW < 500,000 g mol 1. However, it is a good practice to analyze polymer solutions within 24 hr of their preparation [28]. 

The absorption spectrum observed in the pulse radiolysis of solid films of polystyrene is shown in Figure 5. The absorption spectrum around 540 nm is also very similar to the absorption spectrum of polystyrene excimer observed in irradiated polystyrene solutions in cyclohexane as reported previously (2,3). The absorption with the maximum at 410 nm was reported previously and was assigned to anionic species (13,14). The longer life absorptions, attributed to triplet excited polystyrene repeat units and nonidentifiable free radicals, were observed in a wave length region < 400 nm. The absorption spectrum of CMS films obtained in pulse radiolysis showed a peak around 320 nm and a very broad absorption around 500 nm as shown in Figure 6. 

CMS and Polystyrene Solutions in Cyclohexane. Both monomer and excimer fluorescences were observed in the pulse radiolysis of polystyrene solution in cyclohexane. The decay curves of monomer and excimer fluorescences at 287 and 360 nm are shown in Figures 7(a) and (b), respectively. Energy migration on the polymer chain has been discussed elsewhere (15). The dependences of the decay of monomer fluorescence and the rise of excimer fluorescence on the... 

Figure 7. The decay curves obtained from pulse radiolysis of polystyrene solution in cyclohexane (a) monomer and (b) excimer fluorescence monitored at 287 nm and 360 nm, respectively.

Figure 8. Transient absorption spectrum obtained by pulse radiolysis of 200 mM polystyrene solution in cyclohexane.

Polystyrene Solution in CHClj and CCl. In the laser photolysis and pulse radiolysis of polystyrene solution in CHC13 one observes an absorption spectra with maxima at 320 nm and around 500 nm (2,4,17). as shown in Figure 12. 

The transient absorption spectrum obtained in the pulse radiolysis of polystyrene solution in CC1 is shown in Figure 13. The spectrum is very similar to the charge transfer radical complex (PS4+C14-) species. The lifetime is about 200 ns. Consideration of the absorption spectrum and the lifetime suggest that this species is (PS4+C14-)-. The processes leading to formation of this species in liquid CC14 can be written as follows (4,7). 

Reaction Scheme of CMS Resists. The transient absorption spectrum shown in Figure 6 and observed for irradiated CMS films is mainly composed of two components as based on pulse radiolysis data of solid films of CMS and polystyrene, and CMS and polystyrene solutions in cyclohexane, chloroform, and carbon tetrachloride. An absorption with a maxima at 320 nm and 500 nm as due to the charge transfer radical-complex of the phenyl ring of CMS and chlorine atom (see Figure 14) and an absorption with maxima at 312 and 324 nm is due to benzyl type radicals (see Figure 11). 

Cosgrove and Warren 33) used the PGSE method of Packer, et al. 9). with the Meiboom-Gill rf pulse sequence 7> to investigate concentrated polystyrene solutions. 

Fig. 8.9. Power law exponent d as a function of the coil overlap parameter c[ ] at low concentrations. The filled circles are narrow distribution polystyrene solutions (1 77, 316, 318), the open circles are poly(a-methyl styrene) (198, 318). Solvents are chlorinated di-phenyls except the intrinsic viscosity data which were obtained in toluene. Symbols are for polystyrene M= 13.6 x 106, 4 1-8 x 10 , and 0.86 x 106 for poly(a-methyl styrene) O M = 7.5 x 10 , 6 3.3 xlO6, Cr 1.82 xlO6, O- 1.14x10 , a. 0.694x10 , and...

For shear strains greater than approximately 2 the ratio cr(r)/> 0 for a concentrated polystyrene solution was reduced at all observable times. For the large strains, relaxation proceeded more rapidly at short times, but at longer times the residua] stress decayed with about the same time dependence as that in the linear viscoelastic region. 

Frederick, J.E., Tschoegl,N.W., Ferry.J.D. Dynamic mechanical properties of dilute polystyrene solutions dependence on molecular weight, concentration, and solvent. J. Phys. Chem. 68,1974-1982 (1964). 

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