Solvent evaporation from resin solutions

Predicted Compositions during Mixed Solvent Evaporation from Resin Solutions Using the Analytical Solutions of Groups Method... 

An all aromatic polyetherimide is made by Du Pont from reaction of pyromelUtic dianhydride and 4,4 -oxydianiline and is sold as Kapton. It possesses excellent thermal stabiUty, mechanical characteristics, and electrical properties, as indicated in Table 3. The high heat-deflection temperature of the resin limits its processibiUty. Kapton is available as general-purpose film and used in appHcations such as washers and gaskets. Often the resin is not used directly rather, the more tractable polyamide acid intermediate is appHed in solution to a surface and then is thermally imidi2ed as the solvent evaporates. 

Theory. Conventional anion and cation exchange resins appear to be of limited use for concentrating trace metals from saline solutions such as sea water. The introduction of chelating resins, particularly those based on iminodiacetic acid, makes it possible to concentrate trace metals from brine solutions and separate them from the major components of the solution. Thus the elements cadmium, copper, cobalt, nickel and zinc are selectively retained by the resin Chelex-100 and can be recovered subsequently for determination by atomic absorption spectrophotometry.45 To enhance the sensitivity of the AAS procedure the eluate is evaporated to dryness and the residue dissolved in 90 per cent aqueous acetone. The use of the chelating resin offers the advantage over concentration by solvent extraction that, in principle, there is no limit to the volume of sample which can be used. 

For the development of an appropriate strategy for cleavage from the novel syringaldehyde resin, the authors adapted a previously elaborated solution-phase model study on intramolecular Diels-Alder reactions for the solid-phase procedure (Scheme 7.60). The resulting pyridines could be easily separated from the polymer-bound by-products by employing a simple filtration step and subsequent evaporation of the solvent. The remaining resins were each washed and dried. After drying,... 

K[(CH3)3Pt]Pt(CN)4, is isolated from an aqueous solution of the nitrate by adding potassium platinocyanide. A slimy yellow precipitate is formed, insoluble in water and the usual organic solvents except acetone and alcohol. On evaporation from one of these solvents an amorphous resinous greenish-yellow compound is produced which, from determination of the platinum, appears to correspond to K2Pt(CN)4[(CH3)3Pt]2Pt(CN)4. 

Amino-6-chloro-9-[2-(2,2-dimethyl-l,3-dioxan-5-yl)-ethyl]purine (0.59 g, 1.9 mmol) in hydrochloric acid (1.0 M, 4 ml) was stirred at 60°C for 24 hours. The solution was diluted with water and neutralised with Amberlite IR 45. The mixture was filtered, the resin washed with water and the solvent evaporated under reduced pressure. The residue was recrystallised from water to afford 9-(4-hydroxy-3-hydroxymethylbut-l-yl)guanine (238 mg, 49%), melting point 275°-277°C. 

Properties of Pure Caoutchouc.—Pure caoutchouc may be obtained by dissolving rubber in certain solvents, after first removing resins by solution in acetone. The rubber free from resins is treated with chloroform, benzene, or carbon tetra-chloride, all of which are solvents of caoutchouc. Evaporation of the solvent leaves j ure caoutchouc. 

Cast Film - Film produced by pouring or spreading resin dispersion, resin solution, or melt over a suitable temporary substrate, followed by curing via solvent evaporation or melt cooling, and removing the cured film from the substrate. 

Retained solvents may act as plasticizers (i.e., unless the solvent evaporates completely, the deposited resin may not have the same properties as the original solid in its pure state). Retained solvent lowers the glass-transition temperature. If the Tg of the mixture is at or below room temperature, rubbery behavior will result, and consolidant effectiveness will be reduced. Acryloid B72 seemed to retain solvent in films cast from acetone and toluene solutions and then air-dried (12). Further study showed that Acryloid B72 may retain measurable amounts of solvent even after 30 days at room temperature (16, 17). Results are shown in Table II. 

In the case of relatively low-melting solids it is also possible to prepare a thin film by melting and squeezing the sample between two windows. Thin films of nonvolatile liquids or solids can be deposited on the window by solvent evaporation. The sample is first dissolved in a volatile solvent A few drops of the solution are placed on the window. After evaporation of the solvent, a thin film of sample is obtained on the window. The windows can usually be cleaned using carefully dried methylene chloride or acetone. Preparing a thin film from solution or sohdification from the melt are methods well suited to the examination of amorphous materials, such as waxes or soft resins. 

MALDI-MS from Open Channels and Reservoirs. Microfluidic CE separations with on-chip MALDI-MS detection were accomplished by performing the separation in the matrix solution in an open CE channel, followed by solvent evaporation and CE channel scanning with the desorption laser beam. The system was demonstrated for the separation and detection of peptide and oligosaccharide samples. Alternatively, CIEF was performed in PMMA or resin chips with imprinted pseudoclosed channels that were covered only during the lEE step. After focusing, the cover plate... 

Isopropyl ocetote is a wofer-whife pleosont-odored liquid with properties intermediote between ethyl and butyl acetates. It is miscible with most of the common organic solvents such os alcohols, ketones, esters, oils, hydrocarbons, etc., and it is a solvent for nitrocellulose, cellulose ocetate (of low viscosity) and a wide ronge of oils, fats, waxes, gums ond notural and synthetic resins. Like n-propyl ocetote, its solvent power for cellulose esters is increosed when lower aliphatic alcohols are added. It is largely used in the lacquer industry where its slow evaporation rate and blush resistance ore of importance. It is also used in the monufacture of plastics, artificial leather, dopes, films, cements, and in the recovery of acetic ocid from aqueous solutions. 

Solution or a resin exuded by a scale insect, in alcohol or acetone. The color ranges from light yellow to orange the darker shellacs are the less pure. When bleached it is known as white shellac. Applied to surfaces, e.g., wood, shellac forms a hard coating when the solvent evaporates. Shellac is used as a spirit varnish, as a protective covering for drawings and plaster casts, for stiffening felt hats, and in electrical insulation. 

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