Properties of the Solvent (Matrix)

Properties of the Solvent (Matrix)  [c.20]

Properties of the Solvent (Matrix Material)  [c.82]

Furfuryl alcohol is an excellent solvent for many resins. A number of appHcations are based on its reactive solvent properties. When a resin solution is cured, a hard, rigid, thermoset matrix results. The final, cured product often has many outstanding properties. For example, furfuryl alcohol is a reactive solvent for phenoHc resins in the manufacture of refractories for ladles hoi ding molten steel. The furfuryl alcohol provides a low viscosity to allow good mixing of the resin with the refractory particles, then reacts with the phenoHc resin during curing. When heated to high temperatures, the matrix carbonizes, producing a strong refractory bond.  [c.80]

Because of increased production and the lower cost of raw material, thermoplastic elastomeric materials are a significant and growing part of the total polymers market. World consumption in 1995 is estimated to approach 1,000,000 metric tons (3). However, because the melt to soHd transition is reversible, some properties of thermoplastic elastomers, eg, compression set, solvent resistance, and resistance to deformation at high temperatures, are usually not as good as those of the conventional vulcanized mbbers. AppHcations of thermoplastic elastomers are, therefore, in areas where these properties are less important, eg, footwear, wine insulation, adhesives, polymer blending, and not in areas such as automobile tires.  [c.11]

The intensities are plotted vs. v, the final vibrational quantum number of the transition. The CSP results (which for this property are almost identical with CI-CSP) are compared with experimental results for h in a low-temperature Ar matrix. The agreement is excellent. Also shown is the comparison with gas-phase, isolated I. The solvent effect on the Raman intensities is clearly very large and qualitative. These show that CSP calculations for short timescales can be extremely useful, although for later times the method breaks down, and CTCSP should be used.  [c.374]

Poly(methyl methacrylate). Poly(methyl methacrylate) (PMMA) is a hydrophobic polymer that is soluble in some water-miscible solvents, such as dimethyl sulfoxide and DMF (see Methacrylic polymers). Membranes that are produced by casting atactic PMMA into a water gelation bath have poor mechanical and transport properties. However, solution compositions consisting of isotactic and syndiotactic PMMA mixtures form thermoreversihle sol-gel stereotopic complexes that can be cast or spun into hoUow fibers with controUed waU porosity and improved mechanical strength (30,31). Such dope solutions ate spun hot into a subambient (<30° C) atmosphere there, the nascent fiber forms a gel and is subsequendy passed through water to effect an exchange of water for solvent. Since matrix formation is estabUshed during gelation, the microstmcture of the fiber waU does not coUapse when submerged in water, and water-swoUen fiber (ca 65 wt % water content for dope composition spun with 20 wt % polymer) is obtained. Toray Industries, Inc. (Japan) has developed a PMMA hoUow-fiber membrane. Use of this polymer has found some appUcation as a hoUow-fiber artificial kidney. Membrane thickness is in the 30—40 pm range (25).  [c.154]

Isopropyl alcohol [67-63-OJ, also known as isopropanol, 2-propanol, dimethylcarhinol, and j -propyl alcohol, is a colorless, volatile, and flammable Hquid, having a molecular weight of 60.09 and a slight odor resembling a mixture of ethyl alcohol [64-17-5] and acetone [67-64-1]. Isopropyl, the lowest member of the class of secondary alcohols, is generally known as the first petrochemical. Of the lower (C —alcohols, isopropyl alcohol is third ia commercial production, behind methanol (qv) and ethyl alcohol. The 1993, U.S. production was 5.4 x 10 metric tons (1). Production of isopropyl alcohol has been declining at an average annual rate of 3% siace 1980, mosdy because of the declining use of isopropyl alcohol as an acetone (qv) feedstock. An estimated 50% of isopropyl alcohol was used ia solvent appHcations ia 1992 (see Solvents, industrial). Isopropyl alcohol is used for the manufacture of agricultural chemicals, pharmaceuticals (qv), process catalysts, and solvents. Properties, preparation, and uses of isopropyl alcohol have been discussed (2).  [c.104]

Sample Preparation. Sample contamination must be prevented throughout the sampling procedures. Factors that can influence sampling of an analyte iaclude impinged material, residual solvents, sample preserving method, analyte absorption, and potential contamination from the environment. The contamination from sample holders or loss to them have to be considered. No significant changes should occur ia the sample whea it is being held for analysis. Sample stabilization generally iacludes storage at low temperatures however, any stabilization step should be vaUdated. A review of sample composition and properties is advised. This would iaclude number of compouads preseat, chemical stmctures (fuactioaaUty) of compouads, molecular weights of compouads, piC values of compouads, uv spectra of compouads, aature of sample matrix (solveat, fillers, etc), coaceatratioa range of compounds ia samples of iaterest, and sample solubiUty. These properties provide the bases for the selection of an extraction solvent, or a disposable cartridge for sample-extract cleanup such as Supelclean, Quick-Sep, Sep-Pak, or Bond-Elut can be used (2). A detailed discussion of sample preparation methods is available (2). Table 1 fists some samples analyzed by solid-phase extractions from different matrices.  [c.241]

Carbon disulfide was first prepared nearly two hundred years ago by heating sulfur with charcoal. That general approach was the only commercial route to carbon disulfide until processes for reaction of sulfur and methane or other hydrocarbons appeared in the 1950s. Significant commercial production of carbon disulfide began around 1880, primarily for agricultural and solvent appHcations. Both the physical and chemical properties of carbon disulfide are utilized in industry. Commercial uses grew rapidly from about 1929 to 1970, when the principal appHcations included manufacturing viscose rayon fibers, cellophane, carbon tetrachloride, flotation aids, mbber vulcanization accelerators, fungicides, and pesticides. Production of carbon disulfide in the United States has declined in recent years. Other chemical fibers and films, as well as environmental and toxicity considerations related to carbon tetrachloride, have had significant impact on the demand for carbon disulfide. Worldwide annual production capacity in 1991 was approximately 1.3 million tons, with actual production estimated at about one million metric tons.  [c.26]

A paiticularly attiactive and useful feature of supeicritical fluids is that these materials can have properties somewhere between those of a gas and a hquid (Table 2). A supercritical fluid has more hquid-hke densities, and subsequent solvation strengths, while possessiag transport properties, ie, viscosities and diffusivities, that are more like gases. Thus, an SCF may diffuse iato a matrix more quickly than a Hquid solvent, yet still possess a Hquid-like solvent strength for extracting a component from the matrix.  [c.221]

See pages that mention the term Properties of the Solvent (Matrix) : [c.2064]    [c.89]    [c.74]    [c.585]   
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Mass Spectrometry Basics  -> Properties of the Solvent (Matrix)