Deflocculants functions

Adhesives, binders, and deflocculants function is dependent primarily on the presence of polysilicate ions. The soluble silicate used has a ratio range of 2.5 to 4.0, where the ratio is defined as one-half of the ratio of moles of Si to moles of cation (e.g., Na+ or tetramethylammonium ion, TMA+). 

Organophosphoms compounds, primarily phosphonic acids, are used as sequestrants, scale inhibitors, deflocculants, or ion-control agents in oil wells, cooling-tower waters, and boiler-feed waters. Organophosphates are also used as plasticizers and flame retardants in plastics and elastomers, which accounted for 22% of PCl consumed. Phosphites, in conjunction with Hquid mixed metals, such as calcium—zinc and barium—cadmium heat stabilizers, function as antioxidants and stabilizer adjutants. In 1992, such phosphoms-based chemicals amounted to slightly more than 6% of all such plastic additives and represented 8500 t of phosphoms. Because PVC production is expected to increase, the use of phosphoms additive should increase 3% aimually through 1999. 

Dispersed Inhibited Systems. Dispersed inhibitive fluids attempt to combine the use of dispersed clays and deflocculants to derive the fundamental properties of viscosity and fluid loss with other features that will limit or inhibit the hydration of the formation and cuttings. It will be realized these functions are in opposition therefore the ability of these systems to provide a high level of shale inhibition is limited. However, they have achieved a high level of success and in... 

Deflocculants have a relatively low molecular weight. Polymers composed of sodium styrene sulfonate, maleic anhydride, and a zwitterionic functionalized maleic anhydride [738,1411,1412,1415] are suitable. 

In copolymers containing the styrene sulfonate moiety and maleic anhydride units, the maleic anhydride units can be functionalized with alkyl amine [1411-1416]. The water-soluble polymers impart enhanced deflocculation characteristics to the mud. Typically, the deflocculants are relatively low-molecular-weight polymers composed of styrene sodium sulfonate monomer maleic anhydride, as the anhydride and/or the diacid and a zwitterionic functionalized maleic anhydride. Typically the molar ratio of styrene sulfonate units to total maleic anhydride units ranges from 3 1 to 1 1. The level of alkyl amine functionalization of the maleic anhydride units is 75 to 100 mole-percent. The molar concentrations of sulfonate and zwitterionic units are not necessarily equivalent, because the deflocculation properties of these water-soluble polymers can be controlled via changes in their ratio. 

D. G. Peiffer, J. Bock, and J. Elward-Berry. Zwitterionic functionalized polymers as deflocculants in water based drilling fluids. Patent US 5026490,1991. 

Silicates. Both sodium and potassium silicate solids or solutions have valued functionality including emulsification, buffering, deflocculation, and antiredeposition ability. Silicates also provide corrosion protection to metal parts in washing machines, as well as to the surfaces of china patterns and metal utensils in automatic dishwashers. Silicates are manufactured in liquid, crystalline, or powdered forms and with different degrees of alkalinity. The alkalinity of the silicate provides buffering capacity in the presence of acidic soils and enhances the sequestration ability of the builder system in the formulation. The sili-cate/alkali ratios of the silicates are selected by the formulator to meet specific product requirements. Silicate ratios of 1/1 are commonly used in dry blending applications with silicate ratios of 2/1 and higher commonly used in laundry and autodish applications. 

Additives serve a variety of functions in forming , which may be divided into four categories binders, plasticizers, dispersants (also referred to as deflocculants), and lubricants. 

According to their functions, the additives in ceramic process can be classified into four main groups (i) solvents, (ii) dispersants, also known as deflocculants, (iii) binders, and (iv) plasticizers. Additives with other functions, such as lubricants and wetting agents, are also used in some occasions. Successful additives have often been found by trial-and-error approaches, although information is available on chemical principles and applications of additives [71, 72]. 

The shortest distance between the two particles can be larger than the sum of their radii. If the particle surface is covered with polymers there is steric hindrance, which prevents surface contact, so polymers are sometimes used as antiflocculation agents. The sum of the attraction and repulsion potentials is given in Figure 6.6 as a function of the interparticle distance. Once the particles are agglomerated they can only be dispersed again if the attraction between them can be lessened, e.g., with counter ions in the solution. This redispersion is called deflocculation or sometimes repeptization. 

Along with being a forgiving and functional deflocculant, MFO has other benefits to the tape casting process. These other benefits, which will be discussed in the "Organic Interactions section of this chapter, include carrier release. Type II plasticizer (lubricant), and lamination aid. 

Much has been reported in recent years about phosphate ester for use as a deflocculant/dispersant for tape casting slips. Phosphate ester is a very powerful dispersant for many oxide powders, including BaTiOg, AI2O3, and TiOg. Phosphate ester is soluble in either water or a number of organic solvents and is described as an anionic surfactant in polar liquids.Overall conclusions about this additive are that it functions both as an ionic repulsion and steric hindrance deflocculant. 

One example of a very special dual-component polymeric flocculant is poly (ethylene oxide) (PEO) and carboxylated phenolic resin (CPR), usually referred to as a cofactor. It has been shown that this dual flocculant can induce a richness of flocculation behavior depending on the concentration of the two components [40,41]. Flocculation, deflocculation, and reflocculation of cellulose particles were studied for various CPR PEO ratios. It was found that reflocculation is a strong function of this ratio. For low ratios, no reflocculation occurs after a few cycles, whereas for high ratios very limited flocculation and reflocculation occurs. 

Gantrez AN resins have been suggested as a replacement for sodium tripolyphosphate and other phosphates commonly used as detergent builders.The copolymers also function very well as stabilizer additives for heavy-duty liquid detergent formulations and as deflocculants for hard water detergents. As polymeric additives, these resins prevent scale formation or precipitation of alkaline hardness salts from saline waters. If such uses could be fully developed, a substantial market for Gantrez resins could be realized. However, lack of biodegradability and economic considerations would appear to preclude this future. 

Deflocculants are additives that prevent the close approach of particles. They adsorb on the particles and increase the repulsive forces. Coagulants do the opposite function. They reduce the repulsive forces or steric hindrance and promote particle agglomeration. When the agglomeration is produced by bridging action, the substances used are called flocculants, known... 

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