Polystyrene in methyl ethyl ketone

Figure 10.8 shows two sets of data plotted according to these conventions, after correction for the effect of interference. In Fig. 10.8a, HC2/T is plotted against C2 for three different fractions of polystyrene in methyl ethyl ketone. Figure 10.8b shows Kc2/Rg versus C2 for solutions of polystyrene in cyclohexane at five different temperatures. These results are discussed further in the following example.

Figure 10.8 Light-scattering data plotted to give slope-intercept values which can be interpreted in terms of M and B. (a) Polystyrene in methyl ethyl ketone. [From B. A. Brice, M. Halwer, and R. Speiser,/. Opt. Soc. Am. 40 768 (1950), used with permission.] (b) Polystyrene in cyclohexane at temperatures indicated. Units of ordinates are given in Example 10.4. [Reprinted with permission from W. R. Krigbaum and D. K. Carpenter,7. Phys. Chem. 59 1166 (1955), copyright 1955 by the American Chemical Society.]...

Fig. 111.—Experimental values of the interaction parameter %i plotted against the volume fraction of polymer. Data for polydi-methylsiloxane M =3850) in benzene, A (New-ingi6). polystyrene in methyl ethyl ketone, (Bawn et aV ) and polystyrene in toluene, O (Bawn et alP) are based on vapor pressure measurements. Those for rubber in benzene, T (Gee and Orr ) were obtained using vapor pressure measurements at higher concentrations and isothermal distillation equilibration with solutions of known activities in the dilute range.

It will be observed that entropies of dilution (as indicated by i) are highly variable from one system to another. This is contrary to the theory developed from consideration of lattice arrangements, according to which pi should be approximately 1/2 and nearly independent of the system. For polystyrene in methyl ethyl ketone, the entropy of dilution is nearly zero i.e., this solvent is a poor one not because of an adverse energy of interaction but because of the low entropy. First neighbor interactions apparently contribute to the entropy as well as to the energy, a point which was emphasized in Chapter XII. It will be noted also that cyclic solvents almost without exception are more favorable from the standpoint of the entropy than acyclic ones. 

Figure 4. Experimental verification of Equation 20 for polystyrene in methyl ethyl ketone. Polystyrene is in the random-coil conformation (31).

Fig. 27. Numerical predictions of the interface positions normalized with respect to the half-thickness, Loi ns functions of dimensionless time during dissolution of polystyrene in methyl ethyl ketone. TTie upper curve represents the rubbery-solvent interlace while the lower curve represents the glassy-rubbery interface. Theoretical predictions have been adapted from the work of Peppas et al. [59], using the following parameters Lo = 0.0I cm M= 400000 M. = 38000 x = 0.49 Do = 1.1 X 10 " emVs a<, = 20 = 2.15 x 10 s a = 2 and P = 12...

Figure 10. Normalized gel layer thickness versus square root of time for dissolution of polystyrene in methyl ethyl ketone (data of Tu and Ouano...

If we take a given sample of polymer of fixed molecular weight and dissolve it at the same solids in a variety of true solvents , the viscosities of the solutions will be proportional to the viscosities of the original solvents, e.g. 12% polystyrene in methyl ethyl ketone (0 004 poises) - 0 4 poises in ethyl benzene (0007 poises) -1 6 poises in c -dichlorobenzene (0013 poises) - 3-3 poises. This is important, because we can reduce paint viscosity without lowering solids or polymer molecular weight, simply by changing to a less viscous solvent, if a suitable one is available. 

TA4 Tager, A.A. and Galkina, L.A., Thermodynamic stndy of the process of solution of polystyrene in methyl ethyl ketone and ethyl acetate (Rnss.), Nauchn. Dokl. Vyssh. ShkoL, Khim. Khim. TekhnoL, (2), 357, 1958. 

NAK Nakajima, A., Hamada, F., Yasue, K., Fujisawa, K., and Shiomi, T., Thermodynamic studies based on corresponding states theory for solutions of polystyrene in methyl ethyl ketone,Ma omo/. Chem., 175, 197, 1974. 

Fig. 113.—Comparison of observed entropies of dilution (points and solid lines with results calculated for ASi according to Eq. (28) (broken line). Data for polydimethyl-siloxane, M =3850, in benzene, A (Newing ), obtained from measured activities and calorimetric heats of dilution. Entropies for polystyrene (Bawn et in methyl ethyl ketone,, and in toluene, O, were calculated from the temperature coefficient of the activity. The smoothed results for benzene solutions of rubber, represented by the solid curve without points, were obtained similarly.

The results of intrinsic viscosity measurements for four polymer-solvent systems made at the -temperature of each are shown in Fig. 141. The four systems and their -temperatures are polyisobutylene in benzene at 24°C, polystyrene in cyclohexane at 34°C, poly-(di-methylsiloxane) in methyl ethyl ketone at 20°C, and cellulose tricapry-late in 7-phenylpropyl alcohol at 48°C. In each case a series of poly-... 

The block-polymers containing a middle block of polystyrene and two blocks of polyethylene oxide have some unusual properties. They are soluble in methyl ethyl ketone and cannot be precipitated from this solvent by methanol. Addition of water produces a slight cloudiness but still no precipitation although the block polymer is not soluble in pure water. The polymer is also soluble in benzene, but addition of water to this solution causes its precipitation. On the other hand, neither homopolystyrene nor homo-polyethylene oxide or their mixtures are precipitated from benzene solution by addition of water. This strange behaviour is explained by Richards and Szwarc (45) in terms of hydrogen bonding which depends on the chemical potential of water in the aqueous layer and therefore also in the benzene solution. 

In an investigation of the birefringence and stress relaxation of Kraton 101 cast from solution in toluene and in methyl ethyl ketone, Wilkes and Stein (33) considered the relaxation modulus to be a weighted average of the moduli of the pure polybutadiene and polystyrene phases. Ferry and co-workers, in their investigations of time-temperature superposition in polymethacrylates with relatively long side chains, found the com-... 

The coefficients Xl>X2> etc., are determined from observed variation of X with 2. Very often x increases strongly with polymer concentration, particularly in the case of poor solvents. The systems benzene/polyisobutylene, cyclohexane/polystyrene, and methyl ethyl ketone/natural rubber constitute examples. In some cases, however, x seems to be independent of concentration, as proposed by the original Flory-Huggins theory. These findings mainly concern good solvents some examples are benzene/polyisoprene... 

When small amounts of water were deliberately added to butyllithium in hydrocarbon solutions, it was possible to prepare polystyrene with as much as 85% polymer that was insoluble in methyl ethyl ketone under reflux and identified as isotactic polystyrene by X-ray crystallography [194, 195]. Isotactic polystyrene (10-22% crystalline) can be prepared when lithium f-butoxide is... 

Experimental verification of the approximate solution of the dissolution model is presented. An example of polystyrene (Mn = 179,000) dissolution (77) in methyl ethyl ketone that presents the variation of the gel layer thickness with time is compared with die model predictions using equation (39). Figure 10 shows the gel... 

Fig. 3.10 Plot of Y[tc versus c for polystyrene dissolved in methyl ethyl ketone at 310 K (After Billingham).

The osmotic pressure of polystyrene fractions in toluene and methyl ethyl ketone was measuredt at 25°C and the following results were obtained ... 

About 8,000 metric tons of peroxides were consumed in 1972. This consumption was strongly stimulated by the rapid growth in reinforced plastics (Ref 23). The largest volume product is benzoyl peroxide which is used in polystyrene and polyester markets for such items as toys, automobiles, furniture, marine, transportation and mil requirements. Also, methyl ethyl ketone peroxide is used in large volumes to cure (as a catalyst) styrene-unsatur-ated polyester adhesive resins used in mil ammo adhesive applications, as well as in glass fiber reinforced plastic products such as boats, shower stalls, tub components, automobile bodies, sports equipment, etc. The monoperesters are growing slowly because of some substitution of the peroxydicarbonates and azo compds (Refs 8,9 23)... 

Homologous Polymers. As the size of a molecule increases, it is expected that its diffusion coefficient will decrease. Figure 5 shows a plot of D° vs. M for solutions of polystyrene in 2-butanone (methyl ethyl ketone) where the relationship between D° and M may be expressed by the semiempirical formula... 

As shown in Figures 5 and 7 the nature of the solvent does not appear to have any effect on T0 within experimental error. However, the solvent can have a profound influence on the morphology of cast block copolymer specimens. Thus, instead of the continuous polybutadiene phase normally observed, a continuous polystyrene phase appears to exist in Kraton 101 films cast from solution in MEK/THF mixtures (2). Methyl ethyl ketone has a solubility parameter of 9.3, only slightly higher than that of the solvents used in our work. It is clear from the data presented here that our films must have had continuous polybutadiene phases. 

The dynamic viscoelasticity and the thermal behaviour of films of Thermoelastic 125 cast from solutions in four solvents - toluene (T), carbon tetrachloride (C), ethyl acetate (E), and methyl ethyl ketone (M) — have been studied by Miyamato133 The mechanical loss tangent (tan 8) and the storage modulus E dependences exhibit two transitions at —70 °C and 100 °C which have been attributed to onset of motion of polybutadiene and polystyrene segments, respectively. The heights of the polybutadiene peaks on tan 6 curves decrease in the order C > T > E > M, while for polystyrene the order is reversed C < T < E < M. These phenomena have been related to the magnitude of phase separation of the polystyrene and polybutadiene blocks. 

The character of the polymethyl methacrylate data is essentially similar to that found for systems atactic polystyrene-benzene at 25°, 35°, and 50° C. [Kishimoto, Fujita, Odani, Kurata and Tamura (1960) Odani, Kida, Kurata and Tamura (1961)] and also atactic polystyrene-methyl ethyl ketone at 25° C. [Odani, Hayashi and Tamura (1961)], and appears to be fairly general for amorphous polymer-solvent systems in the glassy state. On the other hand, the cellulose nitrate data shown in Fig. 8 appear to manifest features characteristic of crystalline polymer-solvent systems. For example, the earlier data of Newns (1956) on the system regenerated cellulose-water (in this case, water is not the solvent but merely a swelling-agent) and recent studies for several crystalline polymers all show essentially similar characters [see Kishimoto, Fujita, Odani, Kurata and Tamura (I960)]. To arrive at a more definite conclusion, however, more extensive experimental data are needed. 

Odani, H., J. Hayashi and M. Tamura Diffusion in glassy polymers. II. Effects of polymer-penetrant interaction diffusion of methyl ethyl ketone in atactic polystyrene. Bull. Chem. Soc. Japan 34, 817 (1961). 

---