Polystyrene blend separation

In the case of polystyrene blends with poly(vinyl methyl ether) two phase behaviour was found for blends from various chlorinated solvents whereas single phase behaviour was found for blends from toluene The phase separation of mixtures of these polymers in various solvents has been studied and the interaction parameters of the two polymers with the solvents measured by inverse gas chromatography It was found that those solvents which induced phase separation were those for which a large difference existed between the two separate polymer-solvent interaction parameters. This has been called the A% effect (where A% = X 2 Xi 3)-A two phase region exists within the polymer/polymer/solvent three component phase diagram as shown in Fig. 2. When a dilute solution at composition A is evaporated, phase separation takes place at B and when the system leaves the two phase region, at overall... 

Mayo JD, Behai S, Adronov A (2009) Phase separation of polymer-functionalized SWNTs within a PMMA/Polystyrene blends. J Poiym Sci Poiym Chem 47 450-458 Cou JY, Lensch-Falk JL, Hemesath ER, Lauhon LJ (2009) Vanadium oxide nanowire Phase and orientation analyzed by Raman spectroscopy. J Appl Phys 105 034310-1-034310-6 Wang ZL (2004) Functional oxides nanobelts-materials, properties and potential applications in nanosystems and biotechnology. Annu Rev Phys Chem 55 159-196 Bliznyuk VN, Singamaneni S (2009) Polymer carbon nanotube composites. Encyclopedia of nanoscience and nanotechnology, (2012), ASP, Ed. H. S. Nalwa... 

The temperature-independent term A is referred to as the entropic part of. while BjT is called the enthalpic part . The parameters A and B have been tabulated for many polymer blends and we list representative examples in Table 4.3. Isotopic blends typically have small positive x parameters (deuterated polystyrene blended with ordinary polystyrene f/PS/PS is an example) making them only phase separate at very high molar masses. PS/PMMA has four entries in Table 4.3, which reflect the differences encountered by labelling various species with deuterium. PS/... 

Siegfried and co-workers (66,67) investigated thermoplastic IPNs based on SEES triblock copolymers with a polystyrene ionomer. Two subclasses of thermoplastic IPNs were identified those prepared by a sequential polymerization method, and those prepared by mechanically blending separately synthesized polymers. In each case, a polystyrene acid sulfate was neutralized dynamically in the melt with a concentrated solution of sodium hydroxide. The water steamed off rapidly under the reaction conditions. The first subclass resulted in lower melt viscosities, but more nearly equal dual-phase continuity was achieved with the second subclass. The subject of thermoplastic IPNs was recently reviewed by Sperling (68). 

In response to the unsuccessful PANIS/polystyrene blends, other polymers were examined. In addition, in order to reduce the particle size and improve the consistency of the powder, PANIS and the host polymer were ground to a fine powder. The polymer was placed into a small plastic rotary tumbler with nickel shot. Ten to twelve grams of powder were masticated for approximately thirty minutes, resulting in a very uniform powder. The powder was then separated from the shot using a fine mesh screen (approximately 42 mesh or 0.350mm opening). 

SUT Sutton, D., Stanford, J.L., and Ryan, A.J., Reaction-induced phase separation in polyoxyethylene/polystyrene blends. I. Ternary phase diagram, J. Macromol. Sci-Phys. B, 43, 219, 2004. 

GOM Gomez, C.M., Verdejo, E., Figueraelo, J.E., Campos, A., and Soria, V., On the thermodynamic treatment of poly(vinyhdene fluoride)/polystyrene blend unter liquid-liquid phase separation conditions. Polymer, 36, 1487,1995. 

The analysis of polyethylene-polystyrene blends by LCCC is presented in Figs. 20 and 21. With polar Lichrosorb as the stationary phase and decaline-cyclohexane as the mobile phase, using a column temperature of 140°C, blend separations can be accomplished. The adjustment of the critical mobile phase composition is shown in Fig. 20. As can be seen, the elution behaviour of polystyrene changes appreciably even with changes of the mobile phase composition by only 0.1 vol% [149]. This demonstrates the importance of high accuracy and reproducibility of the mixing of desired mobile phase compositions. The critical mobile phase composition corresponds to decaline-cyclohexane 95.9 4.1% by volume, indicated by the molar mass independence of the elution volume. 

Citric acid separation from fermentation broth employs the full allotment of Sorbex beds in addition to the four basic Sorbex zones. The process utilizes a resin instead of a zeolite based adsorbent. The resin is a nonionic cross-linked polystyrene polyvinyl benzene formulation. Operating temperatures for this process are sufficient to overcome diffusion limitations with a corresponding operating pressure to maintain liquid-phase operation. The desorbent consists of water blended with acetone. Subsequent processing steps remove the desorbent from the desired extract product citric acid. 

Unlike simple mixtures of polystyrene and polybutadiene such blends can be thermoplastically processed without phase separation ( splicing ) Furthermore, they can to a certain extent withstand mechanical impact without disintegration. This is because the above-mentioned graft polymers function also as compatibilizer at the borderline of the hard phase and the rubber-elastic dispersed phase (already at concentrations below 3%). 

Deters (14) vibromilled a blend of cellulose and cellulose triacetate. The acetic acid content of cellulose acetate decreased with grinding time (40 h) while that of the cellulose increased, suggesting the formation of a block or graft copolymer or of an esterification reaction by acetic acid developed by mechanical reaction. Baramboim (/5) dissolved separately in CO polystyrene, poly(methyl methacrylate), and poly(vinyl acetate). After mixing equal volumes of solutions of equivalent polymer concentration, the solvent was evaporated at 50° C under vacuum and the resultant product ball-milled. The examination of the ball-milled products showed the formation of free radicals which copolymerized. 

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