Polystyrene benzene system

Such a dramatic change is also reflected in the time-dependence of the dynamical structure factor. The line shape, non-exponential in the gel regime at the 0-temperature, becomes more and more exponential as we increase the temperature from 35°C to 65 C. A single exponential line is observed in polystyrene-benzene system.This is due to the fact that the relative intensity I /Ig of the slow mode (x ) to the fast mode (x ) is proportional to the ratio of the elastic modulus to the osmotic bulk modulus... 

Mutually compatible polymers are relatively rare [84,85], A typical phase diagram of two incompatible polymers and a common solvent is that determined by Kern for the polystyrene - poly(p - chlorostyrene) - benzene system shown in the Fig. 1.11 [86],... 

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. 

Phase Relationships. The first systematic investigation of the two-phase behavior of polymer/polymer/solvent systems was probably made by Dobry and Boyer-Kawenoki (2) for a variety of polymer pairs, and more recently this work was extended by Kern and Slocombe (3) and Paxton (35) to a number of other systems including several vinyl polymers. Typically, the three-component phase behavior is as shown in Figure 19 for the polystyrene/polybutadiene/benzene system (2), where a one-phase (polystyrene/polybutadiene/benzene) region is separated by a phase boundary from a two-phase (polystyrene-rich/benzene and polybutadiene-rich/benzene) mixture. As with any three-component system of this type, a critical point exists somewhere near the maximum of the phase boundary, and appropriate tie lines give the compositions and amounts of the respective phases in the two-phase region. 

Figure 19. Ternary phase diagram for the polystyrene/ polybutadiene/benzene system. (After Dobry and Boyer-Kawenoki (2).)...

Table 2. Parameters for polystyrene-liquid systems Monosubstituted benzene liquids ...

According to the anal3 is of the activity data of rubber-benzene and polystyrene-toluene systems by Zimm and Lundbeeg, the quantity is greater than unity over the whole range of concentration. This is, of course, due to the non-uniform arrangements of molecules in conformity with our discussion in Section 2, On the other hand, the lattice theories give... 

Clarke and Vincent in these studies established the phase diagrams for the free polystyrene-microgel-ethyl benzene systems, two of which are displayed in Fig. 16.2a and b. In all cases, only the stability/instability boun ry is shown. These lines correspond to the locus of the critical volume fraction of free polymer required to induce flocculation (vj ) as a function of the volume fraction of the microgel particles (< 3). 

MIY Miyashita, N., Okada, M., and Nose, T., Critical exponents and phase diagram of polymer blend solutions Polystyrene/poly(methyl methaciylate)/d6-benzene system. Polymer, 35, 1038, 1994. 

Figure 2.17 Dependence of a and v on matrix molecular weight for binary systems dextran water(9) (O). polystyrene toluene(12) ( ), polystyrene trans-decane at Theta point(13) ( ), polystyrene trani-decane as good sol-vent(13) (0), PTEMA toluene(14) ( X polystyrene benzene( 15) (A),...

Dobry and Boyer-Kawenoki have investigated a number of solvent-polymer-polymer systems, with results which confirm all of the qualitative predictions of the theory. Fig. 125 shows their experimental results for the benzene-rubber-polystyrene system with coordinates expressed in weight percent. The symmetry resulting from the stipulations X2 = Xs and xi2 = Xi3 in the case treated theoretically... 

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-... 

In colloid science, colloidal systems are commonly classified as being lyophilic or lyophobic, based on the interaction between the dispersed phase and the dispersion medium. In lyophilic dispersions, there is a considerable affinity between the two constituent phases (e.g., hydrophilic polymers in water, polystyrene in benzene). The more restrictive terms hydrophilic and oleophilic can be used when the external phase is water and a nonpolar liquid, respectively. In contrast, in lyophobic systems there is little attraction between the two phases (e.g., aqueous dispersions of sulfur). If the dispersion medium is water, the term hydrophobic can be used. Resulting from the high affinity between the dispersed phase and the dispersion medium, lyophilic systems often form spontaneously and are considered as being thermodynamically stable. On the other hand, lyophobic systems generally do not form spontaneously and are intrinsically unstable. 

Immobilized cryptates. Like the crowns, cryptates have been immobilized on polymeric backbones. A typical system is given by (221) (Cinquini, Colonna, Molinari, Montanari Tundo, 1976). In this case, the polymeric matrix is polystyrene cross-linked with p-divinyl benzene and the cage is connected to this matrix via a long-chain aliphatic spacer group. This reagent is quite effective as a (triphase) transfer catalyst. 

Use of benzene suspensions containing a neutral rhodium(I)-DIOP complex supported on a cross-linked polystyrene (50) (cf. 13 in Section III,A) for hydrogenation of a-ethylstyrene (to 1.5% ee) and methyl atro-pate (2.5% ee) was less effective than the homogeneous system, as the ethanol cosolvent required for substrate solubility caused a collapse of the resin (296). 

The elution volumes of polystyrene and benzene in the size-exclusion mode were 0.98 and 1.78 ml, respectively (Figure 1.4A). This means that separations by molecular size can be achieved between 0.98 and 1.78 ml in this system. In the normal phase mode the elution volumes of octylbenzene and benzene were 1.98 and 2.08 ml, respectively, in n-hexane solution (Figure 1.4B). This type of chromatography is called adsorption or non-aqueous reversed-phase liquid chromatography. These are adsorption liquid chromatography and non-aqueous reversed-phase liquid chromatography. The elution order of the alkylbenzenes in the reversed-phase mode using acetonitrile was reversed... 

Berlin [69] also confirmed the importance of the presence of OH radicals in his investigation of the polymerisation of polystyrene in the presence of styrene monomer when he found the addition of water to the reaction solvent (benzene) greatly enhanced the yield of polymer. However, latterly it has been argued for these systems that the appearance ofwater decomposition products (e. g. H2O2) led to oxidation of the various impurities, which previously, may have acted as inhibitors in the polymerisation process. 

The reachon of benzene with ethylene or propylene to form ethylbenzene or isopropylbenzene (cumene) is an industrially important transformahon, with ethylbenzene as the key building block for polystyrene and cumene as the feedstock for phenol produchon [55]. Fthylbenzene was originally produced with a Lewis acid catalyst consishng of AlCfi or a Bronsted acidic solid phosphoric acid (SPA) catalyst [56]. Both catalyst systems suffered from equipment corrosion so, in the 1980s the Mobil-Badger vapor phase alkylation process was introduced, which... 

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