Polyethylene/toluene

Oxidised polyethylene Toluene, chloro- Phase-transfer catalysis Filtration (r) [148]... 

Fig. 2.9 Comparison of phase equilibrium calculations using SAFT (dashed lines) and PC-SAFT (solid lines) [76]. (a) Vapor-liquid phase equilibrium of polyethylene-toluene at T=393 K. Filled symbols are experimental data for polymer molecular weight...

As an example for modeling of a vapor-liquid equilibrium in a polymer/solvent system, Fig. 6 shows the results for the polyethylene/toluene binary mixture. The experimental data shown were determined for two different (relatively low)... 

Although Pd is cheaper than Rh and Pt, it is still expensive. In Pd(0)- or Pd(ll)-catalyzed reactions, particularly in commercial processes, repeated use of Pd catalysts is required. When the products are low-boiling, they can be separated from the catalyst by distillation. The Wacker process for the production of acetaldehyde is an example. For less volatile products, there are several approaches to the economical uses of Pd catalysts. As one method, an alkyldi-phenylphosphine 9, in which the alkyl group is a polyethylene chain, is prepared as shown. The Pd complex of this phosphine has low solubility in some organic solvents such as toluene at room temperature, and is soluble at higher temperature[28]. Pd(0)-catalyzed reactions such as an allylation reaction of nucleophiles using this complex as a catalyst proceed smoothly at higher temperatures. After the reaction, the Pd complex precipitates and is recovered when the reaction mixture is cooled. 

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... 

Reinhoudt, Gray, Smit and Veenstra prepared a number of monomer and dimer crowns based on a variety of substituted xylylene units. They first conducted the reaction of 1,2-dibromomethylbenzene and a polyethylene glycol with sodium hydride or potassium Z-butoxide in toluene solution. Mixtures of the 1 1 and 2 2 (monomer and dimer) products were isolated and some polymer was formed . The reaction was conducted at temperatures from 30—60° and appeared to be complete in a maximum of one hour. The authors noted that the highest yield of 1 1 cyclic product was obtained with disodium tetraethylene glycolate instead of dipotassium hexaethylene gly-colate (see also Chap. 2) . Chloromethylation of 1,3-benzodioxole followed by reaction with disodium tetraethylene glycolate afforded the macrocycle (29% yield) illustrated in Eq. (3.20). 

In the case of crystalline polymers it may be that solvents can cause cracking by activity in the amorphous zone. Examples of this are benzene and toluene with polyethylene. In polyethylene, however, the greater problem is that known as environmental stress cracking , which occurs with materials such as soap, alcohols, surfactants and silicone oils. Many of these are highly polar materials which cause no swelling but are simply absorbed either into or on to the polymer. This appears to weaken the surface and allows cracks to propagate from minute flaws. 

Synthesis of comb (regular graft) copolymers having a PDMS backbone and polyethylene oxide) teeth was reported 344). These copolymers were obtained by the reaction of poly(hydrogen,methyl)siloxane and monohydroxy-terminated polyethylene oxide) in benzene or toluene solution using triethylamine as catalyst. All the polymers obtained were reported to be liquids at room temperature. The copolymers were then thermally crosslinked at 150 °C. Conductivities of the lithium salts of the copolymers and the networks were determined. 

Synthesis of 5,10,15,20-Tetrakis(4-(polyethyleneoxy)phenyl)) porphyrin. A slurry of polyethylene methylsulfonic ester (PEvoo-OMs) (20.0 g, 69% functionalized, Mn -780 Daltons) and anhydrous cesium carbonate (CS2CO3) (9.05 g, 27 mmol) in dry toluene (75 ttiL) was prepared and to this mixture a purple solution of 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine (2.9 g, 4.27 mmol) in 75 mL A. A-DMF was added. The reaction mixture was warmed to 95°C with stirring for 18 hours, then the temperature increased to 130°C for a further 5 hours before coohng. The purple-brown solid was collected by filtration, washed thoroughly with methanol and dried under vacuum to yield 21.0 g of the crude ligand, h NMR (toluene-dg, 80°C) 5 8.96 (s), 8.10 (d), 7.22 (d), 4.05 (t), 1.88 (quia), 1.58 (quin.), 1.31 (br. s), 0.88 (t). 

Synthesis of Polyethylene-tethered Phthalonitrile. Polyethylene monoalcohol ( 700 Daltons, 80% functionalized) in pellet form (6.0 g, 8.0 mmol) and anhydrous THF (62 mL) were added to a flask equipped with a magnetic stirring bar. This was allowed to stir for 2 hours before 4-nitrophthalonitrile (2.25 g, 13.0 mmol) was added to the mixture and the suspension heated to reflux. After the polymer had dissolved the CS2CO3 (4.22 g, 13.0 mmol) was added in three equal portions over 3 hours. After 24 hours the reaction was cooled to 60°C then poured into 500 mL of water with stirring. The precipitate was filtered and washed thoroughly with water until pH neutral. The product was then rinsed with A, V-DMF, THF and then dried under vacuum to yield 5.03 g of material. H NMR (toluene-dg, 100°C, 71% conversion) 5 6.86 (d), 6.59 (s), 6.41 (m), 3.41 (t), 3.37 (t), 1.31 (s), 0.88 (t). 

Synthesis of Tetrakis(polyethyleneoxy)phthalocyanine cobalt (II) (9). The polyethylene-tethered phthalonitrile (0.827 g, 1.0 mmol), 1,5-diazabicyclo [4.3.0] non-5-ene (0.062 g, 0.50 mmol) and cobalt acetate (0.044 g, 0.25 mmol) were added to a reaction vial equipped with a magnetic stir bar. The reaction was then heated to 175°C for 2 hours before reducing the temperature to 95°C and adding toluene. The reaction mixture was then poured into methanol, filtered, and the sohd washed further with methanol. The collected product was then dried under vacuum to yield... 

Fig. 21. Recoverable strain as a function of shear stress for polystyrene/toluene solutions with different molar masses at 5 wt%. (+) polyacrylamide/water solutions, ( ) 2 wt%, (x) 2 wt% (with surfactant), (O) 4 wt% and polyethylene melts...

To avoid the time-consuming grinding of plastics samples, Freitag and John [96] have tried dissolving thick samples, i.e. pellets of 3 mm diameter, instead of extracting them. The dissolution, performed with a 1 1 mixture of toluene and 1,2-dichlorobenzene at 100% microwave output during 5 min, yielded satisfactory results (95 % of expected concentration) only for PP, whereas the recovery from the polyethylenes was below 85%. 

I. Jagnandan, H. Daun, T. J. Ambrosio and S. G. Gilbert. Isolation and identification of 3,3,5,5-tetrabis(tert-butyl) stilbenequinone from polyethylene closures containing titanium dioxide and butylated hydroxy toluene. J. Pharm. Sci., 68, 916 (1979). 

Commonly used isocyanates are toluene diisocyanate, methylene diphenyl isocyanate, and polymeric isocyanates. Polyols used are macroglycols based on either polyester or polyether. The former [polyethylene phthalate) or polyethylene 1,6-hexanedioate)] have hydroxyl groups that are free to react with the isocyanate. Most flexible foam is made from 80/20 toluene diisocyanate (which refers to the ratio of 2,4-toluene diisocyanate to 2,6-toluene diisocyanate). High-resilience foam contains about 80% 80/20 toluene diisocyanate and 20% poly(methylene diphenyl isocyanate), while semi-flexible foam is almost always 100% poly(methylene diphenyl isocyanate). Much of the latter reacts by trimerization to form isocyanurate rings. 

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-... 

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