Solvent solventless

Casting of proplnts techniques may be subdivided into A)Manuf of cast homogeneous proplnts B)Manuf of proplnts by slurry casting and C)Manuf of cast composite proplnts A)tAanuf of Cast Homogeneous Propellants. This includes, solvent, solventless- or ball-proplnrs as srarting materials. The method consists of the following operations ... 

Siloxane Solvented/solventless/aqueous Loss of solvent and reaction... 

Solvents solventless eonditions, preferred organie solvents, water, supercritical fluids, expanded liquids, ionie liquids, and liquid polymers (three leetures)... 

Compared to reactions in organic solvents, solventless reactions are often faster, occur in higher yields, and have both environmental and economic advantages. Thus, a solventless condensation of 1,3-diketone 9... 

The solvent selected for a particular reaction should not cause any environmental pollution and health hazard. The use of liquid or supercritical liquid CO2 should be explored. If possible, the reaction should be carried out in aqueous phase or without the use a of solvent (solventless reactions). A better method is to carry out reactions in the solid phase (for details see Chapter 13). 

Solventless Extrusion Process. The solvendess process for making double-base propellants has been used ia the United States primarily for the manufacture of rocket propellant grains having web thickness from ca 1.35 to 15 cm and for thin-sheet mortar (M8) propellant. The process offers such advantages as minimal dimensional changes after extmsion, the elimination of the drying process, and better long-term baUistic uniformity because there is no loss of volatile solvent. The composition and properties of typical double-base solvent extmded rocket and mortar propellant are Hsted ia Table... 

Sihcone products dominate the pressure-sensitive adhesive release paper market, but other materials such as Quilon (E.I. du Pont de Nemours Co., Inc.), a Werner-type chromium complex, stearato chromic chloride [12768-56-8] are also used. Various base papers are used, including polyethylene-coated kraft as well as polymer substrates such as polyethylene or polyester film. Sihcone coatings that cross-link to form a film and also bond to the cellulose are used in various forms, such as solvent and solventless dispersions and emulsions. Technical requirements for the coated papers include good release, no contamination of the adhesive being protected, no blocking in roUs, good solvent holdout with respect to adhesives appHed from solvent, and good thermal and dimensional stabiUty (see Silicon COMPOUNDS, silicones). 

Although waterborne systems were developed in the 1960s, the form of this chemistry that dominates the industry utilizes end-functional, high molecular weight base polymers dissolved in organic solvents. Work on solventless condensation systems continues, but has not yet become commonplace [45,47]. Solvent-borne condensation cure systems are convenient for their ease of pro-... 

A solventless synthesis of pyrazoles, a green chemistry approach, has been described where an equimolar amount of the diketone and the hydrazine are mixed in a mortar with a drop of sulfuric acid and ground up. After an appropriate length of time ( 1 h) the product is purified to provide clean products. Even acyl pyrazoles 42 were obtained under the solvent-less reaction conditions in good yields. 

The choice of reaction solvent is also of concern in the synthesis of new TSILs. Toluene and acetonitrile are the most widely used solvents, the choice in any given synthesis being dictated by the relative solubilities of the starting materials and products. The use of volatile organic solvents in the synthesis of ionic liquids is decidedly the least green aspect of their chemistry. Notably, recent developments in the area of the solventless synthesis of ionic liquids promise to improve this situation [10]. 

All paints consist of a binder (sometimes called a medium) and pigment. Materials consisting of binder only are called varnishes. Most paints and varnishes contain solvent in order to make the binder sufficiently liquid to be applied. The combination of binder and solvent is called the vehicle. Some paints are available without solvent (e.g. solventless epoxies) but these generally require special methods of application (e.g. application of heat) to reduce the viscosity. 

Solventless epoxies These use heat rather than solvent to reduce viscosity, and are generally applied by airless... 

Powder coating is a solventless coating system that is not dependent upon a sacrificial medium such as a solvent, but is based on the performance constituents of solid TP or TS plastics. It can be a homogeneous blend of the plastic with fillers and additives in the form of a dry, fine-particle-size compound similar to flour. The three basic methods are the fluidized bed, electrostatic spray, and electrostatic fluidized bed processes (9). 

Opt for solventless reactions, recycle solvents, or use benign solvents (e.g., water, ionic liquids, supercritical media). 

Extraction or dissolution almost invariably will cause low-MW material in a polymer to be present to some extent in the solution to be chromatographed. Solvent peaks interfere especially in trace analysis solvent impurities also may interfere. For identification or determination of residual solvents in polymers it is mandatory to use solventless methods of analysis so as not to confuse solvents in which the sample is dissolved for analysis with residual solvents in the sample. Gas chromatographic methods for the analysis of some low-boiling substances in the manufacture of polyester polymers have been reviewed [129]. The contents of residual solvents (CH2C12, CgHsCI) and monomers (bisphenol A, dichlorodiphenyl sulfone) in commercial polycarbonates and polysulfones were determined. Also residual monomers in PVAc latices were analysed by GC methods [130]. GC was also... 

Solventless double base propellant. A double base propellant in which gelatinisation is effected by mechanical means without the addition of solvent. 

The first of these, the solventless option, is the best established, and is central to the petrochemical industry, the greenest chemical sector. The second, to use water as the solvent, can be an ideal approach,but suffers from the difficulty of dissolving many organic compounds in water, undemonstrated scale-up, and the cost of the cleanup of organic contaminated water. Supercritical fluids represent a... 

Divalent or higher-valent cations and, in particular, transition metal cations, are likely to be covalently solvated by solvents that are strong electron pair donors (have large solvatochromic P values). This solvation often persists in crystals, so that the salt that is in equilibrium with the saturated solution in such solvents may not be the anhydrous salt (nor the salt hydrate). Equation (2.56) omits any consideration of the solvent of crystallization and pertains to the solventless (anhydrous) salt. For a salt hydrated by n water molecules in the crystal, the activity of water raised to the nth power must multiply the right-hand side of Eq. (2.56) for it to remain valid. A similar consideration applies for salts crystallizing with other kinds of solvent molecules, the activity of the solvent in the saturated solution replacing that of water. Such situations must be... 

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