Polyreactions in solution

There are two different ways for carrying out polyreactions in a solvent. When both the monomer and the resulting polymer are soluble in the solvent, one speaks of a homogeneous solution polymerization on the other hand, if the polymer precipitates during the course of the reaction, it is called precipitation polymerization. By addition of a solvent, different effects are obtained Basically, the viscosity of the reaction mixture is decreased in comparison to a bulk polyreaction this facilitates heat transfer, mass transport, and handling. 

The Schotten-Baumann reaction between dicarboxylic acid dichlorides and diamines can be performed not only in organic solvents, but also, by means of a special experimental technique known as interfacial polycondensation (see Examples 4-5 and 4-11). Both variants have the advantage of short reaction times at low temperature with simple equipment. 

Condensation polymers, especially polyamides, can also be prepared in solution by the Schotten-Baumann reaction at low temperature (see Example 4.11). For this purpose, two rapidly reacting monomers, for example, diamine and dicarboxyhc acid dichloride, are mixed together with stirring in an inert solvent the eliminated hydrogen chloride is trapped with an acid acceptor. 

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The basic characteristics as well as some advantages and disadvantages are illustrated in Sects. 2.2.2 (polyreactions in bulk), 2.2.3 (polyreactions in solution), and 2.2.4 (polyreactions in dispersion). Prior to this some special features... 

The example of polyreactions in microgravity environment mentioned in Section 1 yields similar results. Here, it is additionally necessary to use variable reaction rates, which characterize the photoinitiated polymerization. Summarizing, we have found that the described numerical algorithm is an effective procedure for different applications of the prescribed kind, e.g. in chemical kinetics. It is planned to extend the algorithm to problems, which require the solution of differential-algebraic equations. 

It was not until the synthesis was accomplished in two steps that it became possible to process these polymers from solution. In the first reaction step, two tetrafunctional monomers form a linear and soluble macromolecule by a polyreaction of two of the functional groups of each molecule. Subsequently, cy-... 

Many fluid mixtures encountered in chemical and hydrocarbon processing industries are ill-defined in the sense that they contain far too many components for a detailed compositional analysis and subsequent modeling in terms of pure component mass balances. Common examples of such mixtures are frequently related to processes of high economic relevance and include petroleum and reservoir fluids as well as polymer solutions and polyreaction systems [6]. The concept of continuous thermodynamics is a well-established approach for the modeling of these mixtures [2, 6]. The compositional complexity of the mixture is represented in terms of a time-dependent continuous distribution function of some characterizing fluid property (e.g. molecular weight,... 

The monomeric vesicle solutions of methacrylic, diene, and diacetylene lipids can be pol3nnerized by UV irradiation as schematically shown in fig. 9, In the case of the diacetylene lipids the polyreaction can be observed visually by the color change mentioned above. Electron microscopy can provide direct evidence that the pol3mierized systems still posses liposomal structure (3,20,23). 

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