Reactive liquids

In mass polymerization bulk monomer is converted to polymers. In solution polymerization the reaction is completed in the presence of a solvent. In suspension, dispersed mass, pearl or granular polymerization the monomer, containing dissolved initiator, is polymerized while dispersed in the form of fine droplets in a second non-reactive liquid (usually water). In emulsion polymerization an aqueous emulsion of the monomer in the presence of a water-soluble initiator Is converted to a polymer latex (colloidal dispersion of polymer in water). 

Chemical Reaction (this heat can sometimes exceed the heat of an external fire). Consider bottom venting for reactive liquids. ... 

Walter, Y. L. and V. H. Edwards, Consider Bottom Venting for Reactive Liquids, Chemical Engineering Progress, June 2000, p. 34. 

Methods are used to produce the more costly rapid prototypes include those that produce models within a few hours. They include photopolymerization, laser tooling, and their modifications. The laser sintering process uses powdered TP rather than chemically reactive liquid photopolymer used in stereolithography. Models are usually made from certain types of plastics. Also used in the different processes are metals (steel, hard alloys, copper-based alloys, and powdered metals). With powder metal molds, they can be used as inserts in a mold ready to produce prototype products. These systems enable having precise control over the process and constructing products with complex geometries. 

The RIM process involves the high-pressure impingement mixing of two or more reactive liquid components and injection of the mixture into a closed mold at low pressures. Large and thick products can be molded using fast cycles with relatively low-cost materials. Its low energy requirements with relatively low investment costs make RIM attractive (9). 

The major limitations attendant to the use of sodium in tetrachloride reduction are the necessity to maintain the temperature of the highly exothermic reduction reaction at values between 801 and 883 °C, and the larger volume of the slag generated because of the monovalency of sodium. Another difficulty pertains to the handling of highly reactive liquid sodium. 

This reactive liquid is now normally supplied commercially as a solution (up to 25 wt.%) in pentane, hexane or heptane, because it reacts with ether and ethereal solutions must be stored under refrigeration. Reaction with atmospheric oxygen or... 

An extremely reactive liquid, solid or vapour with a dangerously high thermal capacity in both liquid and vapour state. When heated, the commonest cause of mid-19th century industrial explosions it also bursts containers on cooling to low ambient temperatures. Still a frequent cause of vapour explosions today. 

Polyurethanes, as a class of materials, are one of the most versatile available. By varying the reactants, their amounts and the reaction conditions, one can obtain millable elastomeric gums, hard rigid plastics, reactive liquids, and foams. The versatility is such that it is very difficult to provide a brief summary. 

Most of the monomeric compounds are highly reactive liquids and are rapidly hydrolysed by atmospheric moisture. In the monomeric iminoboranes the N-B bond order is greater than unity and these compounds represent an allene-type system with cumulated multiple bonds as indicated by structure (I) 3S). 

Reactive fibers, 9 486-489 Reactive flame retardants, 11 474-479 brominated, ll 475-477t Reactive gases, 13 456 Reactive groups, types of, 9 178 Reactive hot melt butyl sealants, 22 44 Reactive hot melt polyurethanes, 22 37-38 Reactive hot melt silicones, 22 35 Reactive ion-beam etching (RIBE), 22 184 Reactive ion etching (RIE), 20 278 22 183 of lotus effect surfaces, 22 120 Reactive lead alloys, 14 779 Reactive liquid metal infiltration process, 16 168... 

Reactive liquid-phase sintering, 5 661 Reactive molecules, oliigonucleotides conjugated to, 17 636-637 Reactive organic phosphorus compounds, 11 496-497... 

The aromatic mercaptans react with chlorine to form aryl sulphur chlorides (Zincke) phenyl sulphur chloride is a deep red, very reactive liquid (Lecher) ... 

Reactive liquid film containing both reactants... 

Functionality. For reactive liquid polymers, the most important property is the functionality. Functionality is determined from number average molecular weight (Mn) and hydroxyl number by the following equation ... 

Two of the main considerations in the development of totally reactive liquid photopolymer systems are the resin(s) and the reactive diluents (monomers). The resins play a major role in determining the end properties and therefore the applications of the cured polymer. The reactive diluents are used to provide a fully reactive system with the appropriate reactivity, viscosity, coatability before cure and the desired crosslink density, chemical resistance and dielectric character once it is cured. The pho-toreactive monomers most commonly used are acrylate based derivatives because of the properties they impart, and their high reactivity and wide solubility range. 

B. F. Goodrich Co., Product Description RLP-1 (Hycar Reactive Liquid Polymers), Cleveland, Ohio. 

Generation of droplets containing one or more reactive liquids... 

Thermosets are generally used in advanced composites due to their excellent thermal and dimensional stability, high modulus, and good mechanical properties. Because thermoset resins are inherently brittle, however, some applications require improved fracture resistance. Toughening of thermosets has been achieved through various methods, such as incorporation of reactive liquid rubber [1-9], elastomer [10], or rigid thermoplastics [11-25], and IPN formation with ductile component [26]. 

These applications are a domain that is shared by UV and EB processes, because both can directly convert reactive liquids into solids almost instantly. There are specific areas where EB irradiation is more suitable than the UV curing process. In general, these include applications where thick layers of coatings or adhesives are applied. Other instances are coatings with high levels of inorganic pigments or fillers, which usually cannot be cured by UV radiation because of their opacity. As pointed... 

Linford and coworkers have shown that the attachment of alkenes to H-terminated silicon surfaces can also be initiated by direct mechanical scribing, in a process termed chemomechanical functionalization [145-147]. The reaction of 1-alkenes (as well as 1-alkynes) leads to attachment of the molecule to the surface through two new Si—C bonds. The proposed mechanism is the mechanical cleavage of Si—H and Si—Si bonds, leading to silicon radicals that then react with the reactive liquid. Interestingly, Linford and coworkers have also extended this work to show that chemomechanical functionalization can be carried out not only on H-terminated Si, but also on sihcon covered with oxide, and have shown that the process works with a variety of halides, alcohols, and epoxides in both the liquid and gas phase [146]. 

Internal pressure may be caused by several potential sources. One source is the vapor pressure of the liquid itself. All liquids exert a characteristic vapor pressure which varies with temperature. As the temperature increases, the vapor pressure increases. Liquids that have a vapor pressure equal to atmospheric pressure boil. Another source of internal pressure is the presence of an inert gas blanketing system. Inert gas blankets are used to pressurize the vapor space of a tank to perform specialized functions, such as to keep oxygen out of reactive liquids. The internal pressure is regulated by PV valves or regulators. 

To ensure sufficient contact between the fibers and the matrix, it is desirable to use a liquid precursor with a low viscosity. Reactive liquids are usually preferred over thermoplastics due to the low viscosity of liquids relative to polymer melts. The reactive liquid is typically a multi-component mixture. The reactive liquid may contain a monomer and an activator, which will cause the monomer to polymerize into a solid polymer matrix. 

Ihe polymers of the 2-cyanoacrylic esters, more commonly known as the alkyl 2-cyanoacrylates, are hard glassy resins that exhibit excellent adhesion to a wide variety of materials. The polymers are spontaneously formed when their liquid precursors or monomers are placed between two closely fitting surfaces. Tile spontaneous polymerization of these very reactive liquids and the excellent adhesion properties of the cured resins combine to make these compounds a unique class of single-component, ambient-temperature-curing adhesive of great versatility (Table 3). The materials that can be bonded run the gamut from metals, plastics, most elastomers, fabrics, and woods to many ceramics. 

Volatile reactive liquids present few problems since they generally can be distilled from the vacuum line into a tube equipped with a serum bottle cap (Fig. 9.26). Nitrogen is then admitted to the tube, and the sample is taken with a syringe. Another scheme involves an inlet with a capillary tube or ampule breaker.33 35 This method is potentially useful for vacuum line work, since it is relatively simple to fill and seal off a sample tube attached to the vacuum line. 

An apparatus for the withdrawal of reactive liquids from metal cylinders having a siphon tube is shown in Fig. 1.10b. This setup is operated in much the same way as the syringe apparatus, the main difference being the use of inert gas to force the liquid out of the cylinder containing the siphon tube. 

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