Classification of dispersants

The tristyrylphenol hydrophobic chain adsorbs strongly onto a hydrophobic surface this is due to the poor anchor of the chain to the surface and the high solubility of the polymer in water. 

Graft copolymers of the AB, type are also available, for example AB, graft copolymers based on a PMMA backbone (with some polymethacryHc acid) on which several PEO chains (with average molecular weight 750) are grafted  

This is a very effective dispersant, particularly for high-solids-content suspensions. The graft copolymer is strongly adsorbed onto hydrophobic surfaces with several attachment points by the small PMMA loops of the backbone, and a strong steric barrier is obtained by the highly hydrated PEO chains in aqueous solutions. 

A novel BA graft has been recently synthesised, namely INUTEC SPl (by Orafti in Belgium) consisting of inulin (a linear polyfructose chain A with degree of polymerisation 23), onto which several alkyl chains have been grafted  

The polymeric surfactant adsorbs with multipoint attachment with several alkyl chains. 

The tristyrylphenol hydrophobic chain adsorbs strongly on a hydrophobic surface. 

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A classification of dispersed systems on this basis has been worked out by Pawlow (30) (1910), who introduces a new variable called the concentration of the dispersed phase, i.e., the ratio of the masses of the two constituents of an emulsion, etc. When the dispersed phase is finely divided the thermodynamic potential is a homogeneous function of zero degree in respect of this concentration. 

Table D3.5.1 The Classification of Dispersed Systems is Based on the Nature of the Involved Phases...

Along with the classification of disperse systems based on the phase state of the dispersed phase and the dispersion medium, and their classification as coarse dispersed or colloidal, structured or unstructured, dilute or concentrated, one can also subdivide disperse systems into lyophilic or lyophobic types. Systems belonging to these principally different classes differ in the nature of colloid stability and in the intensity of interfacial intermolecular interactions. High degree of similarity between the dispersed phase and the dispersion medium, and, consequently, compensation of the... 

Some examples of the classification of dispersions stabilized by different types of polymers at room temperature and pressure are listed in Table 7.3. 

In this section we describe the general classification of dispersing agents. The adsorption of surfactants and polymers at the solid/liquid interface was treated in Chapter 5. The various classes can be summarised as follows. 

These descriptive terms are used to classify the degree of nauoscale dispersion as well as global micro- and macroscale dispersion of the nanoparticles in the polymer matrix. Since no numerical standards exist for rating the degree of nanoparticle dispersion in the polymer matrix, use of these terms is strictly qualitative and continues to be area of some controversy, as the classification of dispersion is mostly the opinion of the user. Unfortunately, not all researchers in the nanocomposite area use these terms in the same ways. The definition of intercalated comes from an... 

A universal criterion is that petroleum systems are mostly multiphase and heterogeneous with highly developed interfaces. The degree of dispersity is inversely proportional to a characteristic linear scale of inclusions. The degree of dispersity is a kernel of classification of disperse systems and should be accoimted for as an additional variable in all equations describing the thermodynamic state of a system At nano-scale ranges, this fact becomes especially important (Anisimov, 2004). 

Classification of disperse dyes used for PP fibers can be made according to their performance [475], as follows ... 

A classification of dispersion models for fixed-bed tubular reactors, for example, is given by Froment and Hofmann [2]. For more complex flow patterns more elaborated and complete models are required where the flow fields are described via the solution of the Navier-Stokes equations. The understanding of the complex flow phenomena involved as well as the solution of these vector equations make the problem much more difficult to analyze spending reasonable costs and efforts. The advanced reactor models are discussed in the subsequent chapters, only a brief introduction to the idealized reactor models are presented in this chapter as these models are principal tools for chemical reaction engineers. In particular, the idealized models are easy to calculate, and they give the extreme values of the conversions between which those realized in a real reactor will occur provided there is no bypassing of reactants in the reactor. 

Figure 8.4 Classification of dispersion-corrected density functionals (DFs) [24]. ks and fKS are the unmodified Kohn-Sham potentials and energies, respectively. V oniocai is a nonlocal dispersion correction [24] to the standard Kohn-Sham potential, is a...

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