Polymeric general classification

The first section of this chapter describes the solution properties of polymers, and this is followed by a general classification of polymeric surfactants. Examples are provided of polymeric surfactants and polyelectrolytes that are used as dispersants and emulsifiers. 

As disciissed in Chapter 1, under a scheme proposed by Carothers, polymers are classified as addition or condensation polymers depending on the type of polymerization reaction involved in their synthesis. This classification scheme, however, does not permit a complete difierentiation between the two classes of polymers. A more complete but still oversimplified scheme that is still based on the dilTerent polymerization processes places polymers into three classes condensation, addition, and ring-opening polymers. This scheme reflects the stractures of the starting monomers. Probably the most general classification scheme is based on the polymerization mechanism involved in polymer synthesis. Under this scheme, polymerization processes are classified as step-reaction (condensation) or chain-reaction (addition) polymerization. In this chapter, we will discuss the different types of polymers based on the different polymerization mechanisms. 

In this overview, the first section will on general classification of polymeric surfactants. This is followed by a section on preparation of polymeric snrfactants, with particular reference to sugar-based molecules. This is followed by a discussion of their solntion properties. The next section will be devoted to the adsorption of polymeric snrfactants at the solid/liquid (S/L) interface, whereby a summary will be given to some of the theoretical treatments and the methods that... 

There are three general classifications of living radical polymerization based on differences in the reversible activation reaction step described in the previous section. These three mechanisms are termed dissociation-combination, atom transfer and degenerative chain transfer, respectively [17, 18]. 

This chapter will start with a short account of the general classification and description of polymeric surfactants. This is followed by a summary on then-solutions properties. The adsorption and conformation of polymeric surfactants at the solid-liquid interface will be discussed at a fundamental level and some experimental results will be presented to illustrate the prediction of the theories. The interaction energies between particles or droplets containing adsorbed polymeric surfactants will be briefly described. The final section will give some applications of polymeric surfactants in suspensions, emulsions, and multiple emulsions. 

Figure 2.2 presents the general classification of biopolymers. Natural biopolymers are further divided into various types of proteins, polysaccharides, and nucleic acids. On the other hand, a general classification is not possible for synthetic biopolymers. However, they can be classified in a broad sense according to the method of preparation. For instance, biopolymers synthesized by condensation and addition polymerization reaction are Hsted separately. 

Nonmetal struetural materials, including glass, porcelain, ceramic bricks and tiles, cements, concrete, and graphite, have been reported to be methanol compatible [56]. Compatibility of polymeric materials with methanol has also been reported [58,59]. Table 8 serves as a general classification. A more complete list can be found in Reference 59. The temperature effect can be found in Reference 58 for some plastics in general. 

In addition to these three general classifications, each set of IR and Raman polymeric frequencies can be subclassified according to their individual Raman polarizations and IR dichroic behaviors. The Raman lines may be polarized or depolarized,... 

Beyond N=9, y, (C) becomes higher than y (A). In general, the relative classification of the studied polymers hyperpolarizabilities does not follow the increase in the number of K electrons. An explanation can be found, if we consider the two important factors which are the lengthening of the polymeric chain and bond alternation. In Table 7, are given the MNDO optimized lengths L, of the studied oligomers. The variation of L as a function of N, is plotted in Figure 6. We can see that for any N value, we have approximately the classification ... 

In order to study in more detail the clay minerals, it is first helpful to review briefly the basic structural classification of the silicates in general. Although ultimately complicated, the general progression is logical, and is based on the degree of polymerization of the basic structural unit which is the Si04 tetrahedron (see below). The sequence runs as follows ... 

There are three anions that may loosely claim to be nitrides. Pentazolides (salts of cyclic N ) will all be explosive. Some azides (salts of N3) fall just short of being explosive but all are violently unstable. The true nitrides, nominal derivatives of N3-, are more various. In addition to some ionic structures, there are polymeric covalent examples, and some monomeric covalent ones, while most of those of transition metals are best considered as alloys. Several are endothermic and explosive, almost all are thermodynamically very unstable in air with respect to the oxide. Many are therefore pyrophoric if finely divided and also may react violently with water and, more particularly, acids, especially oxidising acids. A few are of considerable kinetic stability in these circumstances. There is no very clear classification of probable safety by position in the periodic table but polymeric and alloy structures are in general the more stable. Individual nitrides having entries ... 

The rapid classification of polymeric species is an important problem in the area of analytical chemistry in general and of particular relevance to recycling and waste management. To accomplish classification tasks, a combination of spectral data and principal component analysis (PCA) is often employed. 

In many cases, these polymer chains take on a rod-like (calamitic LCPs) or even disc-like (discotic LCPs) conformation, but this does not affect the overall structural classification scheme. There are many organic compounds, though not polymeric in nature, that exhibit liquid crystallinity and play important roles in biological processes. For example, arteriosclerosis is possibly caused by the formation of a cholesterol containing liquid crystal in the arteries of the heart. Similarly, cell wall membranes are generally considered to have liquid crystalline properties. As interesting as these examples of liquid crystallinity in small, organic compounds are, we must limit the current discussion to polymers only. 

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