Dispersants interaction with detergents

The detergent then interacts with the dirt-soil complex to start the process of the latter s removal from the fibers and dispersion into the washing water. 

The principles outlined in Section 3.6.6 apply to both the removal and anti-redeposi-tion of soils, and to detergency in both industrial and personal care situations. There are, however, some differences between the application of detergency in an industrial setting (Section 12.2.1) and in a household setting. For example, whereas industrial cleaning usually involves hard surfaces that cannot mechanically hold soil, fabrics can hold soil mechanically, even after the soil has been removed from the fibre surfaces. In addition, fabrics can usually swell in aqueous solution, are permeable to small molecules, and may contain charged or polar surface groups that can interact with soil. An effective shampoo or skin cleaner needs to displace dirt and keep it dispersed so it does not redeposit before the hair or skin can be rinsed. 

Detergent-dispersant interactions at surfaces. In 4-ball wear tests, an ashless dispersant was found to have an adverse effect on ZDDP-sulfonate-carbonate hardcore RM additives. A high molecular weight Schiff base had the worst effect, followed by a bis-PIBS m-PIBS had the least adverse effect. Interactions among additives affects valve train wear. One of the effects is that a succinimide together with other additives increases the decomposition temperature of ZDDP (Ramakamur, 1994 Shirahama and Hirata, 1989). 

As for all additives, interactions with other additives in solution, Fig. 3.16, and competition for surface reaction sites together with the effect of environmental factors such as temperature, blow-by gases, water and fuel dilution have variable effects on the formation of the film. Because ZDDPs are much more widely used as antiwear performance additives compared to other classes of compounds, these additive effects will now be discussed in greater detail than has been the case for other classes of anti-wear/friction additives. In particular the influence of structure, concentration, dispersant, detergent, antioxidancy and friction modifier on friction and wear will be discussed. In addition the influence of NO c and H2O will be briefly illustrated. 

The detergent then interacts with the dirty soil to start the process of removal from the fibers and dispersion into the washing water. In order to be able to inhibit the soil once removed to readsorb on the clean fiber, one uses polyphosphates or similar suitable inorganic salts. These salts also increase the pH (around 10) of the washing water. 

Mixtures of ethylene and methylene distearamide with hydrocarbons have also been claimed to be effective particle-oil antifoams for control of detergent foam in front-loading textile washing machines [38]. Such mixtures represent weU-known antifoams for general application (see, e.g.. Table 4. A3). They may be prepared by milling the mixtures or by cooling a melt of the mixtures (since the solubility of distearamides at ambient temperatures is low) to form particulate dispersions in hydrocarbons. The particles of these alkylene distearamides are intrinsically hydro-phobic [39] and have the properties necessary for rupture of the relevant pseudoemulsion films (see Chapter 4). Unlike the soaps and alkyl phosphoric acid esters, there is no requirement for interaction with any ingredient, such as water hardness, present in the wash solution. 

As a result of their ability to adsorb onto surfaces or interfaces and markedly alter the free energy of that surface or interface [56], surfactants find broad use in many products that contact the skin. In these products, surfactants provide the following functions wetting, emulsification, foaming, dispersive activity, and detergency. This section reviews the interactions of surfactants with the skin and the outcome of those interactions. 

Oil additives function primarily by their interaction with tribological surfaces. The addition of an appropriate additive to a lubricant increases its mechanical efficiency and reduces friction and wear, thus avoiding surface damage. Nevertheless, the lubricant additives can also interact with each other to provide beneficial or antagonistic effects. These effects need to be assessed and balanced such as in the case of adding detergents and dispersants to reduce deposits and provide anticorrosion protection with the antagonistic effects... 

Water-insoluble liquid soils are commonly known as oily soils. Naturally occurring oily soils include hydrocarbons, saturated or unsaturated fatty acids, esters of fatty acids, and alcohols. Natural oily soils found on textiles are mixtures of oily components. Frequently, oil soils contain dispersed solid particulate matter (e.g., used motor oil). The most important properties of oily soils are their viscosity [1,2], polarity [3,4], and solubility in detergent solutions or dry-cleaning solvents. The removal of oily soil by detergency is facilitated by a low viscosity at the wash temperature. The polarity of soil affects adhesion of the soil on fibers, interaction with... 

Mixtures of metallic detergents, such as phenates, sulfonates, phosphonates, and salicylates with ashless dispersants such as succinimides and benzylamine, together with zinc dialkyldithiophosphate (ZDDP), can lead to new effects. The possible interactions between these main additives used in lubricating formulations when dissolved/dispersed in hydrocarbon media are shown in Fig. 2.8 together with an indication of the intensity of those respective interactions. 

Surface-active agents, or surfactants, all share interesting physicochemical characteristics at surfaces and interfaces. Surfactants (detergents and dispersants) are long chain hydrocarbons with polar headgroups which are called dipoles. Surfactants are molecules which consist of two well defined parts one which is oil-soluble hydrophobic and another which is water-soluble hydrophilic. The hydrophobic part is non-polar and usually consists of aliphatic or aromatic hydrocarbons. The hydrophilic part is polar and interacts strongly with water. 

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