Additives foaming agents

But consider what happened in the foaming example when additional foaming agents were introduced. The single factor foaming was deliberately changed. An experiment was performed. The result of the experiment clearly disproved any hypothesized causal relationship between alcohol content and foaming. 

As described in Sect. 4.2.1 foamed polyurethanes can be obtained especially through the so-called water-crosslinking of suitable polyol/diisocyanate combinations. Carbon dioxide liberated during the reaction partially causes the expansion of the foam. For a number of reasons additional foaming agents (in the form of low-boiling liquids or CO2) are added in practice, i.e., in order to vary the foam density and the pore size. 

Thermally stable foam additives, such as alkylaryl sulfonates and C -C g alpha-olefin sulfonates, are being used in EOR steam flooding for heavy od production. The foam is used to increase reservoir sweep efficiency (178,179). Foaming agents are under evaluation in chemical CO2 EOR flooding to reduce CO2 channeling and thus increase sweep efficiency (180). 

In addition, buffer salts such as disodium hydrogen phosphate may be used to prevent the pH of the aqueous phase falling during polymerisation. Small amounts of an anti-foam agent may be employed to reduce frothing when discharging from the vessel at the end of the polymerisation process. 

Cocamide DEA (or MEA or TEA) is used as a foaming agent, to make lather. The other surfactants generate a certain amount of suds, but this foaming agent is added to get the amount just right. In addition to its foam-stabilizing effects, it is also a viscosity booster—it s thick. 

Foam cement is a special class of lightweight cement. The gas content of foamed cement can be up to 75% by volume. The stability of the foam is achieved by the addition of surfactants, as shown in Table 10-9. A typical foamed cement composition is made from a hydraulic cement, an aqueous rubber latex in an amount up to 45% by weight of the hydraulic cement, a latex stabilizer, a defoaming agent, a gas, a foaming agent, and a foam stabilizer [359,362]. Foamed high-temperature applications are based on calcium phosphate cement [257]. 

W. T. Osterloh. Long chain alcohol additives for surfactant foaming agents. Patent US 5333687, 1994. 

Polyether-based foams account for more than 90% of all flexible polyurethane foams. The properties of foams are controlled by the molecular structure of the precursors and the reaction conditions. In general, density decreases as the amount of water increases, which increases the evolution of carbon dioxide. However, the level of water that can be used is limited by the highly exothermic nature of its reaction with isocyanate, which carries with it the risk of self-ignition of the foamed product. If very low density foams are desired, additional blowing agents, such as butane, are incorporated within the mixing head. 

The coal-water mixture fed to the boilers has to be formulated to a certain specification. This is done with the proper inclusion of additives to facilitate combustion. The recommended additives include a petroleum-based surfactant (polysulfones or polycar-boxylates), a stabilizing (e.g. xanthan gum), a biocide and an anti-foaming agent (such as a silicone base). 

Indicates additive discussed in this chapter. Other additives discussed in this chapter but not defined above are adjuvants, foam stabilizers and foaming agents. These are described in Table 11.2. For historical reasons Modified starch is an exceptional category, because all the other categories are functional uses, whereas modified starches are a group of substances. 

PVC is regarded as perhaps the most versatile thermoplastic resin, due to its ability to accept an extremely wide variety of additives Plasticizers, stabilizers, fillers, processing aids, impact modifiers, lubricants, foaming agents, biocides, pigments, reinforcements. .. 

Using a laboratory technique previously developed to evaluate the performance of chemical foaming agents in XLPE foam, metallocene polyolefins are evaluated at various addition levels to branched LDPE to determine their effect on general foam quality (cell size, density, appearance). The laboratory method is discussed, and conclusions on acceptable levels of the metallocene resins are offered. 5 refs. 

As it turned out, CFCs were ideal for the purpose. The members of this chemical family are nonflammable, noncorrosive, nontoxic, odorless, and very stable. Within a short period, they became widely popular for a variety of industrial applications. In addition to their applications in refrigeration systems, they became popular as aerosol propellants, cleansing agents for electrical and electronic components, and foaming agents in the manufacture... 

Catalysts, colorants, foaming agents, biocides, lubricants, and antistats are also used as additives for polymers. Although foaming agents reduce the specific gravity, the other cited additives, when used in moderate amounts, have little effect on the physical or thermal properties of the polymers. 

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