System, Nonreactive

Diluents will also affect the performance properties of the adhesive. Diluents generally lower the degree of crosslinking and degrade the physical properties of the cured epoxy. This reduction in crosslink density increases the resiliency of the adhesive, but it also reduces tensile strength as well as heat and chemical resistance. These effects are more pronounced at elevated temperatures than at room temperature. The degree of these effects will depend on whether the diluent has epoxy functionality (reactive diluents) or whether the diluent is incapable of reacting with the epoxy system (nonreactive diluents). 

Thermal Simple system Nonreactive, iimited multicomponents, material produced, moderate production rate... 

The free maleic acid content in maleic anhydride is determined by direct potentiometric titration (166). The procedure involves the use of a tertiary amine, A/-ethylpipetidine [766-09-6J, as a titrant. A tertiary amine is chosen as a titrant since it is nonreactive with anhydrides (166,167). The titration is conducted in an anhydrous solvent system. Only one of the carboxyhc acid groups is titrated by this procedure. The second hydrogen s dissociation constant is too weak to titrate (166). This test method is not only used to determine the latent acid content in refined maleic acid, but also as a measure of the sample exposure to moisture during shipping. 

Model Reactions. Independent measurements of interfacial areas are difficult to obtain in Hquid—gas, Hquid—Hquid, and Hquid—soHd—gas systems. Correlations developed from studies of nonreacting systems maybe satisfactory. Comparisons of reaction rates in reactors of known small interfacial areas, such as falling-film reactors, with the reaction rates in reactors of large but undefined areas can provide an effective measure of such surface areas. Another method is substitution of a model reaction whose kinetics are well estabUshed and where the physical and chemical properties of reactants are similar and limiting mechanisms are comparable. The main advantage of employing a model reaction is the use of easily processed reactants, less severe operating conditions, and simpler equipment. 

Sihcone polymer plasticizers have historically been used in many formulations. These plasticizers (qv) are of the same Si—O backbone as the functional polymers but generally are terrninated with trimethyl groups which are unreactive to the cure system. This nonreactivity means that, if improperly used, the plasticizer can migrate from the sealant and stain certain substrates. Staining has been a widely pubHcized flaw of sihcone sealants, but the potential of a formulation to stain a substrate can be minimized or eliminated with proper formulation work. In general, this is accompHshed by not using plasticizers for formulations developed for stain-sensitive substrates. 

Consider a closed, nonreacting PTT system containing n moles of a homogeneous fluid mixture. The mole numbers of the individual chemical species sum to... 

Although derived for a reversible process, equation 46 relates properties only, irrespective of the process, and therefore apphes to any change in the equiUbtium state of a homogeneous, closed, nonreacting system. 

Similar stability and reactivity have also been observed for bridged-Cp systems. The catalyticaHy active (CH2)2Si(C (CH2)4)2ThR2, where R = Cl [89597-06-8] alkyl, CH2CgH [89597-10A] aryls, or H [89597-11-5], Similar to Group 4 transition-metal Zeigler-Natta catalysts, stable cationic Th(IV) species, eg, [Cp 2ThCH2] [108834-69-17, have been isolated with a host of noncoordinatiag/nonreactive anions. MetaHacycle formation has also been... 

Depending on the characteristics and performance requirements, adhesives systems are frequendy modified with diluents (reactive and nonreactive) and polyfunctional high performance resins, as weU as with fillers of various types. 

Equation (4-5) shows that for the single-phase, nonreacting, closed system specified,... 

This equation may be apphed to a closed, nonreactive, two-phase system. Each phase taken separately is an open system, capable of exchanging mass with the other, and Eq. (4-16) may be written for each phase ... 

Effects of System Physical Properties on Ug and Ui When designing packed towers for nonreacting gas-absorption systems for... 

When an equilibrium reaction occurs in a vapor-hquid system, the phase compositions depend not only on the relative volatility of the components in the mixture, but also on the consumption (and production) of species. Thus, the condition for azeotropy in a nonreactive system = x, for all i) no longer holds true in a reactive system and must be modified to include reaction stoichiometry ... 

The transformed variables describe the system composition with or without reaction and sum to unity as do Xi and yi. The condition for azeotropy becomes X, = Y,. Barbosa and Doherty have shown that phase and distillation diagrams constructed using the transformed composition coordinates have the same properties as phase and distillation region diagrams for nonreactive systems and similarly can be used to assist in design feasibility and operability studies [Chem Eng Sci, 43, 529, 1523, and 2377 (1988a,b,c)]. A residue curve map in transformed coordinates for the reactive system methanol-acetic acid-methyl acetate-water is shown in Fig. 13-76. Note that the nonreactive azeotrope between water and methyl acetate has disappeared, while the methyl acetate-methanol azeotrope remains intact. Only... 

Inert Gas A noncombustible, nonreactive gas that at sufficient concentrations renders the combustible material in a system incapable of supporting combustion. 

The results for the chemical potential determination are collected in Table 1 [172]. The nonreactive parts of the system contain a single-component hard-sphere fluid and the excess chemical potential is evaluated by using the test particle method. Evidently, the quantity should agree well with the value from the Carnahan-Starling equation of state [113]... 

Fig. 20 shows the density profiles in the reactive and nonreactive parts of the system. The number density in the reactive part is very high (a one-component density at the center of this part is 0.596, so the number density of two components is twice as high). However, the density in the nonreactive part is much lower and equal to 0.404. The application of the test particle methods is therefore easy. There is a well-established density plateau in the nonreactive part consequently, the determination of the bulk density in this part is straightforward and accurate. 

To conclude, the introduction of species-selective membranes into the simulation box results in the osmotic equilibrium between a part of the system containing the products of association and a part in which only a one-component Lennard-Jones fluid is present. The density of the fluid in the nonreactive part of the system is lower than in the reactive part, at osmotic equilibrium. This makes the calculations of the chemical potential efficient. The quahty of the results is similar to those from the grand canonical Monte Carlo simulation. The method is neither restricted to dimerization nor to spherically symmetric associative interactions. Even in the presence of higher-order complexes in large amounts, the proposed approach remains successful. 

Inert Gas A nonflammable, nonreactive gas that can be nsed to render the combnstible material in a system incapable of snpporting combnstion. 

The volume fractions and mole fractions become identical in ideal gas mixtures at fixed conditions of pressure and temperature. In an isolated, nonreactive system, the molar composition does not vary with temperature. 

For a nonreactive system, the material balance may be done either on a mass or on a molar basis. 

Adiabatic Reaction Temperature (T ). The concept of adiabatic or theoretical reaction temperature (T j) plays an important role in the design of chemical reactors, gas furnaces, and other process equipment to handle highly exothermic reactions such as combustion. T is defined as the final temperature attained by the reaction mixture at the completion of a chemical reaction carried out under adiabatic conditions in a closed system at constant pressure. Theoretically, this is the maximum temperature achieved by the products when stoichiometric quantities of reactants are completely converted into products in an adiabatic reactor. In general, T is a function of the initial temperature (T) of the reactants and their relative amounts as well as the presence of any nonreactive (inert) materials. T is also dependent on the extent of completion of the reaction. In actual experiments, it is very unlikely that the theoretical maximum values of T can be realized, but the calculated results do provide an idealized basis for comparison of the thermal effects resulting from exothermic reactions. Lower feed temperatures (T), presence of inerts and excess reactants, and incomplete conversion tend to reduce the value of T. The term theoretical or adiabatic flame temperature (T,, ) is preferred over T in dealing exclusively with the combustion of fuels. 

The above considerations, as applied to nonreactive and/or reactive igniter systems, have not been adjusted for the perturbing effect of the addition of propellant combustion products during the propagation period. This... 

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