Polystyrene+ethylbenzene

Large Scale Polystyrene-Ethylbenzene High Viscosity Two-Phase Flow Test Report, DIERS/.AIChE, 1986, 76 pages. 

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.)...

This example uses the Chen et al. method to show how experimental results can be compared graphically to model predictions. The file containing experimental data for the polystyrene-ethylbenzene system must first be created using the POLYDATA program. This file contains all the data for this system in the finite concentration VLE data base. The Tutorial for POLYDATA describes how to create this file. 

No.8, 20th April 1999, p.2684-9 CONFORMATIONALLY SENSITIVE INFRARED VIBRATIONS OF THE SYNDIOTACTIC POLYSTYRENE/ETHYLBENZENE COMPLEX... 

Brimhall, S.L. Myers, M.N. Caldwell, K.D. Giddings, J.C. Study of temperature dependence of thermal diffusion in polystyrene/ethylbenzene by thermal field-flow fractionation. J. Polym. Sci., Polym. Phys. Ed., 1985, 23, 2443. 

Based on the work by Vrentas et al. (1983) for polystyrene-ethylbenzene, where Xip = 0.35, and similar systems, fS u resulting in... 

Commercial polystyrenes are normally rather pure polymers. The amount of styrene, ethylbenzene, styrene dimers and trimers, and other hydrocarbons is minimized by effective devolatilization or by the use of chemical initiators (33). Polystyrenes with low overall volatiles content have relatively high heat-deformation temperatures. The very low content of monomer and other solvents, eg, ethylbenzene, in PS is desirable in the packaging of food. The negligible level of extraction of organic materials from PS is of cmcial importance in this appHcation. 

Benzene is alkylated with ethylene to produce ethylbenzene, which is then dehydrogenated to styrene, the most important chemical iatermediate derived from benzene. Styrene is a raw material for the production of polystyrene and styrene copolymers such as ABS and SAN. Ethylbenzene accounted for nearly 52% of benzene consumption ia 1988. 

Uses Ethylbenzene is used primarily to make styrene. Styrene is used to make polystyrene, a low-cost and versatile polymer. It is also copolymerized with other vinyl monomers to make rubber (SBR) and moldable plastics (ABS). 

The performance of clay materials (Halloysite, Pyrophyllite, Montmorillonite K-30) in the degradation of polystyrene (PS) was investigated in this study. The catalysts showed good catalytic activity for the degradation of PS with high selectivity to aromatics liquids. Styrene is the major product, and ethylbenzene is the second most abundant one in the liquid product. 

Figure 1.4 Different modes of chromatographs using the same column. Column, 5 pm Cj8-bonded silica gel, 15 cm x 4.6 mm i.d. Eluent A, tetrahydrofuran B, n-hexane C, acetonitrile flow rate, 0.5 ml min-1 at ambient detection, UV 260 nm. Peak 1, benzene, 2, ethylbenzene, 3, butylbenzene 4, octylbenzene and 5, polystyrene.

In a study in which styrene was stripped from polystyrene, Latinen (1962) concluded that his theory correctly described the dependence of mass transfer rates on screw speed and flow rate. This conclusion was based on the agreement obtained between the measured and predicted exit concentration of styrene over a broad range of screw speeds and flow rates (Fig. 8). But, agreement between the theoretical expression and the experimental data was obtained using a diffusion coefficient of the order of 3 X 10 m sec , at 2(X)°C a value which is unrealistically high for this system. If the system ethylbenzene-polystyrene—which has a diffusion... 

Biesenberger and Kessidis were able to correlate their experimental data at atmospheric pressure in terms of N in accordance with Eq. (36) [their Eqs. (4)-(9)], but the diffusion coefficient which they computed using Eq. (36) along with the experimental data was found to be roughly D = 10 m sec" at 177°C. Again, if the ethylbenzene-polystyrene system is used as a basis for comparison, Duda et al. (1982) report a value of 3 x 10"" m /sec at 178°C, which is considerably smaller than the value obtained by Biesenberger and Kessidis (1982). In the experiments con-... 

Fig. 15. Comparison of the measured and predicted exit concentrations obtained by Todd for a polystyrene polymer containing ethylbenzene as the volatile component. Data were obtained in a twin-screw extruder. From Todd (1974).

One of the earliest published studies on extraction in twin-screw extruders was conducted by Todd (1974). In this work devolatilization was conducted under vacuum using two different polymeric systems, polystyrene in one and polyethylene in the other. In the case of polystyrene, styrene was not used as the volatUe component so as to avoid problems associated with further polymerization or depolymerization instead, use was made of mixtures of thiophene and toluene or ethylbenzene. Todd found good agreement between the measured exit concentrations of the volatile component and the predicted values using Pe = 40 in the solution to Eq. (38) (see Fig. 15). The value of 5 in Eq. (39) was not reported and it is not known whether a value was chosen to provide a fit with the data or whether it was known a priori. In any event, what is clear is that the exit concentration varies with IVwhich suggests that mass transfer is occur-... 

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... 

Uses Preparation of polystyrene, styrene oxide, ethylbenzene, ethylcyclohexane, benzoic acid, synthetic rubber, resins, protective coatings, and insulators. 

FIGURE 6.3 Molecular weight of polystyrene (PS) as a function of solvent and solvent concentration A = -butylmercaptan, B = carbon tetrabromide, C = carbon tetrachloride, D = o-cresol, E = p-cresol, F = m-cresol, G = phenol, H = s-ec-butylbenzene, 1 = cumene, J = ethylbenzene, K = chloroform, L = -heptant, M = toluene, N = benzene, where [S] = concentration of chain-transfer agent and [M] = concentration of styrene monomer. 

Because of the experimental difficulties involved, there are relatively few reliable Cp values available in the literature. The values that are available [Eastmond, 1976a,b,c Ham, 1967] for any one polymer often vary considerably from each other. It is often most useful to consider the small model compound analog of a polymer (e.g., ethylbenzene or isopropylbenzene for polystyrene) to gain a correct perspective of the importance of polymer chain transfer. A consideration of the best available Cp values and those of the appropriate small-model compounds indicates that the amount of transfer to polymer will not be high in most cases even at high conversion. Cp values are about 10-4 or slightly higher for many polymers such as polystyrene and poly(methyl methacrylate). 

Migration of ethylbenzene Ifom polystyrene into various foods has been reported. The following ethylbenzene levels were found sour milk beverages, < 2.5-6 pg/L noodle soup, 15-21 pg/L noodle curry, 89-153 pg/kg and wantan soup 9-28 pg/L (ECETOC, 1986). Migration of ethylbenzene Ifom polystyrene containers into dairy products resulted in concentrations of ethylbenzene ranging from 2 to 4 pg/kg in yoghurt and 4 pg/kg for chocolate dessert (Ehret-Henry et al, 1994). 

At present all commercial polystyrene (with average molecular weights between 100,000 and 400,000) is manufactured by radical polymerization, which yields atactic polymers.476 Peroxides and azo compounds are commonly used initiators. The suspension process (usually as a batch process in water at 80-140°C) produces a product with relatively high residual monomer content.223 More important is the continuous solution process (usually in ethylbenzene solvent at 90-180°C), which yields high-purity product. Styrene can be copolymerized with numerous other monomers.477 One of these copolymers, the styrene-divinylbenzene copolymer produced by free-radical polymerization, has a crosslinked stucture and is used in... 

Table IX shows the effect of two chemically very different organic liquids on the glass temperature of polystyrene (2). Ethylbenzene, with a chemical structure very similar to that of the polystyrene monomer unit, greatly lowers Tg and therefore, is a much more efficient plasticizer for polystyrene than paraffin oil, with its completely aliphatic structure.

Divinylbenzene. This is a specialty monomer used primarily to make cross-linked polystyrene resins. The largest use of divinylbenzene (DVB) is in ion-exchange resins for domestic and industrial water softening, Ion-exchange resins are also used as solid acid catalysts for certain reactions, such as esterification. Divinylbenzene is manufactured by dehydrogenation of diethylbenzene, which is an internal product in the alkylation plant for ethylbenzene production,... 

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