Polystyrene substituted

RhCI3 Cross-linked polystyrene-substituted with —CH2PPh2 and —CH2NMe2 polymethylacrylate with —0(CH2)2NMe2 and —0(CH2)2CN n-Heptene 23... 

HiPtCI Cross-linked polystyrene substituted with cyanomethyl groups Acetylene with H5iCI3 63, 75... 

Rh(CO)2CI]2 Cross-linked polystyrene substituted with —PPh2 —PBu2 —SH —CH2NMe2 or — P(OMe)2 1-Hexene 45... 

RhCl3 H20 Poly-4-vinylpyridine cross-linked polystyrene substituted with Me2N-, Me2NCH2-, Me2NCH2CH2- 1- Hexene 2- Hexene Cyclohexene 57... 

Sherrington and coworkers161 have examined the chlorination of phenol by J-butyl hypochlorite in the presence of cross-linked polystyrenes substituted by pendant polymethylene chains terminated with anionic or cationic head groups, as well as some hydrophilic acrylic polymers, in four solvents water, methanol, 1,2-dichloroethane and xylene. The polymers exerted a significant influence on the chlorination, particularly in polar solvents. However, no changes in the regioselectivity of the chlorination, in comparison to homogeneous systems, was observed. 

Judovits L, Bopp RC, Gaur U, Wunderlich B (1986) Heat capacities of polystyrene, substituted polystyrenes and crosslinked polystyrenes. J. Polymer Sci., Polymer Hiys. Ed. 24 2725... 

In recent years, a great deal of effort has been devoted to the study of antithrombogenic polymers (1-3).It has been shown in the present authors laboratory (4-7) that modified insoluble polystyrenes substituted either with sulfonate or amino acid sulfamide groups, exhibit anticoagulant activity, when suspended in plasma. This property can be attributed to the adsorption of thrombin and antithrombin III, at the plasma-polymer interfaces (7-9). 

Malhotra SL (1983) Ultrasonic modification of polymers. 2. Degradation of polystyrene, substituted polystyrene, and poly(n-vinyl carbazole) in the presence of flexible chain polymers. J Macromol Sci A A18 1055-1085... 

Columns packed with porous, polymeric particles, such as divinylbenzene-cross-linked polystyrene, substituted methacrylates, and polyvinyl alcohols can also be used for HPLC method development, " as can modified alumina and zirconia stationary phases. ... 

Polymer 59 is an example of a polystyrene substituted with sidechain zinc phthalocyanine moieties. These polymers formed aggregates in solution even with small degrees of phthalocyanine incorporation." Aggregates result from phthalocyanine (cofacial) stacking interactions. 

Thus, the protective strategy in conjunction with living anionic polymerization successfully works to afford well-defined functional polystyrenes substituted with alcoholic and phenolic hydroxyl groups, diols, and triols. The silyl ether-, cyclic acetal-, and ortho ester-protected functionalities are effective for this purpose. This strategy may possibly be applied to other useful functional styrene derivatives and will be discussed in the next section. 

Materials are being developed to exhibit both photochromic and photographic behaviors one such system is based on a substituted indolinospiro-hen opyrene embedded in a polystyrene matrix (26). This system acts as a photochromic system at low exposure in the uv range and at high exposure it functions as a photographic system. The image can be devisualized by heat and can be restored many times with uv irradiation. 

Foaming polystyrene resin prepared by blending with gas deHvers an opaque, low density sheet useful for beverage-bottle and plastic can labels as a water-resistant paper substitute (see Styrene polymers). 

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. 

Nickel dialkyldithiocarbamates stabili2e vulcani2ates of epichlorhydrinethylene oxide against heat aging (178). Nickel dibutyldithiocarbamate [56377-13-0] is used as an oxidation inhibitor in synthetic elastomers. Nickel chelates of substituted acetylacetonates are flame retardants for epoxy resins (179). Nickel dicycloalkyldithiophosphinates have been proposed as flame-retardant additives for polystyrene (180—182) (see Flame retardants Heat stabilizers). 

OC-Methylstyrene. This compound is not a styrenic monomer in the strict sense. The methyl substitution on the side chain, rather than the aromatic ring, moderates its reactivity in polymerization. It is used as a specialty monomer in ABS resins, coatings, polyester resins, and hot-melt adhesives. As a copolymer in ABS and polystyrene, it increases the heat-distortion resistance of the product. In coatings and resins, it moderates reaction rates and improves clarity. Physical properties of a-methylstyrene [98-83-9] are shown in Table 12. 

Table 3. Glass-Transition Temperatures of Substituted Polystyrene...

Capture efficiency is the fraction of generated contaminant that is directly captured by the hood. Measurement of capture efficiency involves measuring concentration of process-generated contaminant or a tracer material. Using process-generated contaminant requires use of instruments suited to each specific contaminant and its conditions (temperature, pressure, concentration, form, etc.). In order to facilitate these measurements, a tracer is often substituted for the process-generated contaminant. The tracer is usually a gas (sulfur hexafluoride, nitrous oxide, helium, or similar), but an aerosol (particles) can also be used (potassium iodide, polystyrene particles, microbiological particles, etc.). The chosen tracer should be as similar to the real contaminant as possible, but at the same time should... 

The von Richter cinnoline process was further extended to solid-phase synthesis. The route began from benzylaminomethyl polystyrene and the required diverse o-haloaryl resins represented by 21 were prepared from substituted o-haloanilines. A Pd-mediated cross-coupling reaction with 21 and the alkynes provided the alkynylaryl derivatives represented by alkyne 22. The von Richter cyclization reaction with hydrobromic or hydrochloric acid in acetone/HaO and cleavage from the resin occurred in the same step to furnish the cinnoline derivatives 23 in 47-95% yield and 60-90% purity (no yield reported for each entry). 

More recently, Tietze and Steinmetz (96SL667) used the patented polystyrene-resin methodology for for the solid-phase synthesis of a large number of diverse )3-keto esters 40a-h. These were reacted with phenylhydrazine in THF at room temperature to give hydrazones 41a-h that were then cychzed into 2-phenyl 5-substituted pyrazol-3-ones 42a-h by heating in toluene at 1(X)°C (Scheme 12). 

When used as substitutes for asbestos fibers, plant fibers and manmade cellulose fibers show comparable characteristic values in a cement matrix, but at lower costs. As with plastic composites, these values are essentially dependent on the properties of the fiber and the adhesion between fiber and matrix. Distinctly higher values for strength and. stiffness of the composites can be achieved by a chemical modification of the fiber surface (acrylic and polystyrene treatment [74]), usually produced by the Hatschek-process 75-77J. Tests by Coutts et al. [76] and Coutts [77,78] on wood fiber cement (soft-, and hardwood fibers) show that already at a fiber content of 8-10 wt%, a maximum of strengthening is achieved (Fig. 22). 

Ethylene is not unique in its ability to form a polymer. Many substituted ethyl-enes, called vinyl monomers, also undergo polymerization to yield polymers with substituent groups regularly spaced on alternating carbon atoms along the chain. Propylene, for example, yields polypropylene, and styrene yields polystyrene. 

Figures 12-12 and 12-13 document that trap-free SCL-conduction can, in fact, also be observed in the case of electron transport. Data in Figure 12-12 were obtained for a single layer of polystyrene with a CF -substituted vinylquateiphenyl chain copolymer, sandwiched between an ITO anode and a calcium cathode and given that oxidation and reduction potentials of the material majority curriers can only be electrons. Data analysis in terms of Eq. (12.5) yields an electron mobility of 8xl0 ycm2 V 1 s . The rather low value is due to the dilution of the charge carrying moiety. The obvious reason why in this case no trap-limited SCL conduction is observed is that the ClVquatciphenyl. substituent is not susceptible to chemical oxidation.

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)... 

In place of N-methylimidazole (Melm), only dimethylaminopyridine (DMAP) could be substituted. The solid-supported amines piperidinomethyl- or morpholinomethyl polystyrene resins, pyridine, and tertiary amines like triethylamine andN-methylmorpholine were not effective. 

To remove carboxylic acid, the crude product is redissolved in 20 mL of methylene chloride and is shaken for 30 min with 1 g of aminomethylated polystyrene resin with a substitution of 1.02 mmol/g, available from Novabiochem (Note 3). After filtration and washing of the resin with 50 mL of methylene chloride, the filtrates were collected together in a 250-mL flask and the solvent was removed on a rotary evaporator. 

The reactivities of substituted monomers are different from those of the unsubstituted ones. For example, in crosspropagation an electron donating methyl group introduced to the C = C bond of a vinyl monomer makes it less reactive in anionic copolymerization, while it increases its reactivity in a cationic process. Thus, in THF at 25 °C the reactivity of isoprene towards polystyrene anion is lower by about a factor of 2 than that of butadiene (only one end of this bivalent monomer is affected),... 

A one-pot synthesis of thiohydantoins has been developed using microwave heating [72]. A small subset of p-substituted benzaldehydes, prepared in situ from p-bromobenzaldehyde by microwave-assisted Suzuki or Negishi reactions, was reacted in one pot by reductive amination followed by cyclization with a thioisocyanate catalyzed by polystyrene-bound dimethyl-aminopyridine (PS-DMAP) or triethylamine, all carried out under microwave irradiation, to give the thiohydantoin products in up to 68% isolated yield (Scheme 16). 

Even the lowest value of LOI reported in Table 8 for the 4-/so-propylphe-noxy-substituted POP is still considerably higher than those of the most common organic polymers (17.4 for polyethylene, 17.8 for polystyrene and 18.3 for ABS rubber [283])... 

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