Latex carboxylate soaps

Figure 3. Effect of various straight-chain potassium C18 carboxylate soaps upon mechanical stability of natural rubber latex (2) (KCt8) potassium stearate (KC18) potassium oleate (KC18") potassium elaidate (KC18Z) potassium linoleate (KC=ZZ) potassium linolenate (KC1H12(oli)) potassium 12-hydroxy stearate ...

It is important to point out that our investigation of counterion effects in carboxylate soaps has so far been concerned almost exclusively with laurate soaps. Laurate soaps were chosen partly because they are generally convenient to handle in that many of them are readily soluble in water to give solutions of low viscosity, and partly because, as has been shown above, laurate soaps are very effective in enhancing the mechanical and chemical stability of natural rubber latex. It must therefore be borne in mind that the conclusions which have been drawn from this investigation concerning effects attributable to counterion variation in laurate soaps may not be generally valid for carboxylate soaps as a family. 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

Latex Types. Latexes are differentiated both by the nature of the coUoidal system and by the type of polymer present. Nearly aU of the coUoidal systems are similar to those used in the manufacture of dry types. That is, they are anionic and contain either a sodium or potassium salt of a rosin acid or derivative. In addition, they may also contain a strong acid soap to provide additional stabUity. Those having polymer soUds around 60% contain a very finely tuned soap system to avoid excessive emulsion viscosity during polymeri2ation (162—164). Du Pont also offers a carboxylated nonionic latex stabili2ed with poly(vinyl alcohol). This latex type is especiaUy resistant to flocculation by electrolytes, heat, and mechanical shear, surviving conditions which would easUy flocculate ionic latexes. The differences between anionic and nonionic latexes are outlined in Table 11. 

We also note that carboxylate ions which are chemically combined at the polymer-water Interface are known to be considerably more effective in conferring mechanical stability upon a latex than are carboxylate ions which are held at the interface by adsorption. Presumably this is because the latter are able to move laterally in the particle surface, whereas the former are not.) We propose that a given number of adsorbed soap anions is more effective in conferring mechanical stability if able to move independently of... 

In a quest for different applications various numbers of polymers have been chosen to prepare encapsulated and functionalized magnetic particles by soap-free emulsion polymerization. Examples are amide- and carboxyl-functionalized magnetic latex for protein immobilization [156], and thermally sensitive and carboxyl-functionalized particles for antibody purification [157], bioprocesses... 

PEG-15 phytosterol PEG-20 phytosterol PEG-25 phytosterol PEG-30 phytosterol Stearamine oxide stabilizer, foam prods. Isostearamidopropylamine oxide stabilizer, foam SBR latex systems Ammonium stearate stabilizer, foam shampoo Apricotamide DEA Cl 2-14 alkyl dimethyl betaine Cocamidopropyl betaine Cocamidopropyl lauryl ether Cocamine oxide Disodium lauroamphodiacetate Laureth-6 carboxylic acid Linoleamide DEA Myristamine oxide Palm kernelamide DEA PEG-3 cocamine PEG-3 lauramide Polyquaternium-7 Undecylenamide DEA stabilizer, foam skin care Disodium lauroamphodiacetate Hydrolyzed wheat gluten Olivamidopropyl betaine stabilizer, foam soaps PEG-40 lanolin PEG-85 lanolin... 

Polychloroprene latex. Anionic or non-ionic latices can be used. The polymer determines the initial tack and open time, the bond-strength development and hot bond strength, the application properties and the adhesive viscosity. Anionic latices are stabilized with rosin soaps. Carboxylated polychloroprene latex is stabilized with polyvinyl alcohol and provides better freeze-thaw stability than the anionic types [78]. 

While most latex house paints fall in the nonreactive class, many applications use a subsequent cross-linking reaction to enhance durability. In a simple example, pendant hydroxyl and carboxyl groups on a polymer chain may not react with each other, while the polymer is suspended as a latex. But when the film is dried and heated, esterification can take place. It may be possible to wash off a fresh film with soap and water, but not one that has aged and become cross-linked. The advantages in an exterior house paint are obvious because cleaning np is easy but permanence (water resistance) inCTeases with time. 

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