Surfactants nonreactive cationic

Table 13.1 Nonreactive cationic surfactants used to modify montmorillonite. ... 

The two terms, one for the reaction in micelles (right hand side, first term) and water (right-hand side, second term of this equation are primarily composed of independently measurable or estimable constants, Xa, P, Fm, cmc, 2, Xa, and Xn and experimentally fixed concentrations, [St], [Nt], and [Xj]). Above the cmc, the second term rapidly diminishes, which is important for catalyzed reactions (most studies), but makes a significant contribution for inhibited reactions (not considered). The first term defines the relationships between k2 and [Sj] and [Xt].[Xt] = [St] because X is added as a counterion with surfactant and [Nt] is often small in comparison. The first term describes a maximum in k2 with increasing [St] because the numerator is first order and the denominator is second order in surfactant concentration. Figme 7 shows a simulated kinetic plot based on (15) (real data is seldom this uniform). It illustrates the effect of the added cationic surfactant on a reaction between the neutral substrate. A, an anionic reactant, N, and the anionic nonreactive counterion, X, with increasing [St] and the effect of increasing Xa on... 

The cationic Surfmers produced much smaller particle sizes in the emulsion polymerization of styrene and styrene/butyl acrylate than the amphoterics (20-50 nm versus 100-300 nm). Some of the latter, however, conferred to the copolymer lattices stability to electrolytes and freeze-thaw [24]. Similar, but nonreactive surfactants produced from succinic anhydride gave similar stability but had much inferior water resistance [25]. 

First, define the elements, independent species, dependent species, solid species, adsorbed cations on matrix, and surfactant-associated cations, based on the compositions shown in Table 10.8. These defined elements and species are listed in Table 10.9. This is a critical step in building an alkaline model. For this case, 6 elements (N = 6), 6 independent species and 8 dependent species with a total of 14 fluid species (] = 14), 2 solid species (K = 2), 3 adsorbed cations on matrix (I = 3), and 2 surfactant-associated cations (M = 2) are defined. Note that the subscripts a and s for CafOH), and CaCO, mean in aqueous and solid states, respectively. A, FIAo, and HA represent petroleum acid anion, petroleum acid in oleic phase, and petroleum acid in aqueous phase, respectively. The last fluid species must be F1A . In principle, we can arbitrarily select N independent species. Practically, we select the species that are similar to the elements, and they are simple species so that other dependent species can be defined from them with equilibrium constants. Chlorine is a nonreactive species therefore, it is not selected as an independent species. Of course, it will not appear in any reaction equation. 

The majority of miniemulsions reported in the literature have been stabilized with anionic surfactants such as sodium dodecyl sulfate (SDS), probably because of the widespread use of anionic surfactants in conventional emulsion polymerization, and due to their compatibility with neutral or anionic monomers and anionic initiators. Other types of surfactant have also been used, such as cationic, nonionic, and mixed nonionic/anionic, reactive as well as nonreactive surfactants. The surfactants useful for miniemulsion polymerization should meet the same requirements as in the conventional emulsion polymerization. 

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