FOAMING AGENT Subject

Several agents are currently used for plugging high permeability strata. These include small fibers that are carried in the waterflood and deposited in the high permeability zgnes and chemical reactions forming insoluble precipitations. Some of the current methods available, for example polymers or foams, are subject to deterioration and are costly. This gives them limited application as they are not able to penetrate deep into the strata. 

This is an important stabilising effect in foams which are formed from solutions of soaps, detergents, etc. If a film is subjected to local stretching as a result of some external disturbance, the consequent increase in surface area will be accompanied by a decrease in the surface excess concentration of foaming agent and, therefore, a local increase in surface tension (Gibbs effect). Since a certain time is... 

In the foam process, a concentrated solution of the finishing chemicals compounded with suitable foaming agents and, If necessary, foam stabilizers Is mechanically foamed so as to Incorporate by volume 50 to 95% air, This foam, having an appearance quite similar to shaving cream, Is applied to the fabric. The foam-coated fabric Is then subjected to a mechanical pressure which collapses the foam. The fabric Is then dried and cured In the conventional manner. 

The preparation of foams of PCHE and copolymers has also been claimed [79]. A combination of a low-boiling hydrocarbon (butane) foaming agent and a higher boiling hydrocarbon plasticizer (toluene) were used to prepare foams. The increased heat distortion temperature of PCHE has been proposed to lead to utility in insulating foams for hot water pipes and similar applications. In addition, the superior weatherability of this material would allow use in applications in which the product was subjected to UV exposure. 

Further subjects in the spotlight are foaming agents, notably CFCs, which are now forbidden in many countries. Other additives or processing aids under debate, such as brominated and other halogenated flame retardants, cadmium and lead heat stabilisers and release agents which cause damage to the ozone layer, are discussed in more detail in Table 3.5 of Chapter 3. 

Recent research and field tests have focused on the use of relatively low concentrations or volumes of chemicals as additives to other oil recovery processes. Of particular interest is the use of surfactants as CO (184) and steam mobility control agents (foam). Also combinations of older EOR processes such as surfactant enhanced alkaline flooding and alkaline-surfactant-polymer flooding have been the subjects of recent interest. Older technologies polymer flooding (185,186) and micellar flooding (187-189) have been the subject of recent reviews. In 1988 84 commercial products polymers, surfactants, and other additives, were listed as being marketed by 19 companies for various enhanced oil recovery applications (190). 

If the fuel is removed or consumed by the subject combustion process, no more fuel supplies will be available for the combustion process to continue and it will cease. In some cases, a fuel is not literally removed from a fire, but is separated from the oxidization agent. Foam suppression methods are good examples where the a barrier is introduced to remove the fuel from the air (i.e., oxidizer). Storage tanks and pipeline fires can use pump-out methods and inventory isolation, respectively, as methods of fuel removal. 

Formaldehyde is also released from aminoplasts and their derivatives, such as urea-formaldehyde foam insulation (UFFI), wood adhesives, and textile finishing agents. It is this supplemental, industrial source of formaldehyde that has become the subject of risk analysis. Should we allow products that serve our daily comfort to alter our environment by releasing an irritating vapor with a pungent odor ... 

Similarly, a recent patent combines aminolysis and hydrolysis reactions for achieving polyurethane decomposition.98 Thus, scrap polyurethane is reacted with a mixture of diethanolamine and aqueous sodium hydroxide. The simultaneous attack of these agents on the polymeric chains allows the reaction time to be appreciably shortened. The reaction product, obtained as an emulsion, is subjected to a second treatment with propylene oxide in order to transform the amines and ureas present in the mixture into polyols, giving a final product which is substantially free of any hydrogen-containing nitrogen atoms. The polyols produced have been found to be particularly suitable for the preparation of fresh polyurethane polymer which can be used as an elastomer or flexible foam. 

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