Polystyrene solubility

Fig. 11. Variation with the swelling ratio of the polystyrene block of the thickness d of polystyrene soluble layer and the specific surface for the copolymers SB.33 and SB.34.

Enholm [12] has carried out free radical allyl transfer reactions using a non-cross-linked polystyrene, soluble polymer 77. Model reactions of bro-mo ester 78 with allyltin reagents gave products 79 and 80 in excellent yield (Scheme 17). 

Domains in position 2 on Figure 7.17 are filled after free volume voids were already filled. This increases free volume and for this reason the mechanical strength of material decreases. The effect is more dramatic because mineral oil is incompatible with polystyrene (solubility parameters of mineral oil and polystyrene are 7.6 and 9.1 (cal cm ), respectively) therefore mineral oil-mineral oil attractive forces are stronger than mineral oil-polystyrene forces. Thus, the excess of mineral oil (above the amormt required to fill free volume voids in position 1) accumulates in the mineral oil domains (position 2), which increase in size with amormt of mineral oil increasing. It was determined that the domain sizes are kept low ( 0.2 nm) below 6 vol% mineral oil in a low molecular polystyrene but they are about 9 nm at 8 vol%. At 9 nm, domains are above the critical size which causes phase separation and thus more catastrophic decrease in mechanical strength. 

Polystyrene, (soluble), incorporating an acid chloride group Polymer-saccharide (C-6) ester". Alkaline hydrolysis (NaOMe-Dioxane) C-1 Bromide viacw-1,2-orthoester Guthrie er a/., 1971, 1973... 

Phosphenated polystyrene (soluble) [Rh(CO)Cl]2 Rh(PPh3)3Cl PdCl2(PhCN)2 PtCl2(PhCN)2 Bayer and Schurig, 1975... 

Manzotti, R., Tang, S., and Janda, K. D. (2000) Improved synthesis of prostanoids on a non-crosslinked polystyrene soluble support. Tetrahedron 56, 7885-7892. 

The main structural results on these copolymers were obtained for products of low styrene content 41,154) polymerized with Ti-based systems. In all cases the total polymer products can be separated into two parts atactic polystyrene (soluble in ketones) and the true copolymers. These products do not contain isotactic polystyrene 41), which verifies the suggestion that this atactic polystyrene is formed on cationic active sites rather than cm the usual Ziegler-type centers. Copolymers of low styrene content have the styrene units isolated independently from the rit2 value. This was proved by IR and NMR spectra studies. Styrene units absorb at frequencies characteristic for isolated groups at 550-560cm" and at 1075cm" when the styrene content is 5.7-19.1% 41,154), and give rise to a resonance at t 298 in the NMR spectrum (154). 

Heat 20 g. of styrene (Section IX,6) with 0 -2 g. of benzoyl peroxide (Section IV,196) on a water bath for 60-90 minutes. A glass-bke polymer (polystyrene) is produced. The polymer is soluble in benzene and in dioxan and can be precipitated from its solution by alcohol. 

Phase Separation. Microporous polymer systems consisting of essentially spherical, intercoimected voids, with a narrow range of pore and ceU-size distribution have been produced from a variety of thermoplastic resins by the phase-separation technique (127). If a polyolefin or polystyrene is insoluble in a solvent at low temperature but soluble at high temperatures, the solvent can be used to prepare a microporous polymer. When the solutions, containing 10—70% polymer, are cooled to ambient temperatures, the polymer separates as a second phase. The remaining nonsolvent can then be extracted from the solid material with common organic solvents. These microporous polymers may be useful in microfiltrations or as controlled-release carriers for a variety of chemicals. 

The organic and aqueous phases are prepared in separate tanks before transferring to the reaction ketde. In the manufacture of a styrenic copolymer, predeterrnined amounts of styrene (1) and divinylbenzene (2) are mixed together in the organic phase tank. Styrene is the principal constituent, and is usually about 90—95 wt % of the formulation. The other 5—10% is DVB. It is required to link chains of linear polystyrene together as polymerization proceeds. DVB is referred to as a cross-linker. Without it, functionalized polystyrene would be much too soluble to perform as an ion-exchange resin. Ethylene—methacrylate [97-90-5] and to a lesser degree trivinylbenzene [1322-23-2] are occasionally used as substitutes for DVB. 

Styrene is a colorless Hquid with an aromatic odor. Important physical properties of styrene are shown in Table 1 (1). Styrene is infinitely soluble in acetone, carbon tetrachloride, benzene, ether, / -heptane, and ethanol. Nearly all of the commercial styrene is consumed in polymerization and copolymerization processes. Common methods in plastics technology such as mass, suspension, solution, and emulsion polymerization can be used to manufacture polystyrene and styrene copolymers with different physical characteristics, but processes relating to the first two methods account for most of the styrene polymers currendy (ca 1996) being manufactured (2—8). Polymerization generally takes place by free-radical reactions initiated thermally or catalyticaHy. Polymerization occurs slowly even at ambient temperatures. It can be retarded by inhibitors. 

In a second example, a cell—gelatin mixture is cross-linked with glutaraldehyde (43). When soluble enzyme is used for binding, the enzyme is first released from the cell, then recovered and concentrated. Examples of this type of immobilization include binding enzyme to a DEAE-ceUulose—titanium dioxide—polystyrene carrier (44) or absorbing enzyme onto alumina followed by cross-linking with glutaraldehyde (45,46). 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

Tables 5.4 and 5.5 predict that unvulcanised natural rubber (8 = 16.5) will be dissolved in toluene (8 = 18.2) and in carbon tetrachloride (8 = 17.5) but not in ethanol (8 = 26.0), all values being in units ofMPa. This is found to be true. Similarly it is found that there is a wide range of solvents for polystyrene in the solubility parameter range 17.2-19.7 MPa. ...

Styrene is a colourless mobile liquid with a pleasant smell when pure but with a disagreeable odour due to traces of aldehydes and ketones if allowed to oxidise by exposure to air. It is a solvent for polystyrene and many synthetic rubbers, including SBR, but has only a very limited mutual solubility in water. Table 16.1 shows some of the principal properties of pure styrene. 

Being a hydrocarbon with a solubility parameter of 18.6MPa - it is dissolved by a number of hydrocarbons with similar solubility parameters, such as benzene and toluene. The presence of a benzene ring results in polystyrene having greater reactivity than polyethylene. Characteristic reactions of a phenyl group such as chlorination, hydrogenation, nitration and sulphonation can all be performed with... 

In effect this means that, to achieve reasonable toughness, semicompatible rubbers should be used. Semicompatibility may be achieved (a) by selecting mixtures of slightly different solubility parameter from the polystyrene, (b) by... 

High-performance size exclusion chromatography is used for the characterization of copolymers, as well as for biopolymers (3). The packings for analyses of water-soluble polymers mainly consist of 5- to 10-/Am particles derived from deactivated silica or hydrophilic polymeric supports. For the investigation of organosoluble polymers, cross-linked polystyrene beads are still the column packing of choice. 

The major advantage of the capillary hydrodynamic chromatography is that the mobile phase does not need to have similar solubility parameter as the sample and packing material. (In SEC, nonsize exclusion effects may be observed if the solubility parameter of the sample, packing material, or mobile phase is considerably different.) Therefore, the hydrodynamic size of polymers can be studied in a 0 solvent and even in a solvent that is not compatible with any currently available SEC packing material (9). Figure 22.4 is an example of polystyrene separation in both THF and diethyl malonate. Diethyl malonate is the 0 solvent of polystyrene at 31-36 C. 

Gel permeation ehromatography (GPC)/normal-phase HPLC was used by Brown-Thomas et al. (35) to determine fat-soluble vitamins in standard referenee material (SRM) samples of a fortified eoeonut oil (SRM 1563) and a eod liver oil (SRM 1588). The on-line GPC/normal-phase proeedure eliminated the long and laborious extraetion proeedure of isolating vitamins from the oil matrix. In faet, the GPC step permits the elimination of the lipid materials prior to the HPLC analysis. The HPLC eolumns used for the vitamin determinations were a 10 p.m polystyrene/divinylbenzene gel eolumn and a semipreparative aminoeyano eolumn, with hexane, methylene ehloride and methyl tert-butyl ether being employed as solvent. 

Figure 14 The variation of average size of the polystyrene particles by the average solubility parameter of the homogeneous alcohol-water dispersion medium. (From Ref. 89. Reproduced with the permission of John Wiley Sons, Inc.)...

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