Contents 3 Synthetic Emulsifiers

The above experimental results show that wax particles can affect the rheological properties of the interfacial film between the water and oil phases. In order to confirm these phenomena we added a synthetic wax to the jet fuel/syn-thetic formation-water system and took the interfacially active fractions from Daqing crude oil as emulsifier. The content of the synthetic wax in jet fuel was 5% and the melting temperature of the synthetic wax was 54-56°C. The results shown in Fig. 11 demonstrate that the interfacial shear viscosity increased as the temperature rose to the range between 20 and 30° C, and the interfacial shear viscosity decreased when the temperature was higher than 30°C. It is obvious that the presence of synthetic wax particles at the interface makes the properties of the interfacial film greatly different from those shown in Fig. 2. 

Synthetic adhesives and acrylic paints are but two examples of synthetic polymers widely used in art and conservation. However, these products generally were not specifically developed for conservation purposes, and most manufacmrers, citing trade secrets, refuse to reveal the precise contents of their products. This is especially true of such additives as antioxidants, flocculants, antifoamers, emulsifiers, etc. Often companies have changed the contents of products, keeping the same name while not informing the customers about these changes. A weU-known example is that of ketone resin varnishes. An extensive review of the thermal analysis of polymers is given in Chapters 4 and 5 of this book. Here we note a few of the applications of pyrolysis in the area of art and conservation. 

Anionic surfactants, based on alkyl sulfates, are widely used as the basis for synthetic detergents, emulsifiers, stabilisers, and so on. Alkyl sulfates R0S03Me (where Me is Na, K and so on) under the conditions of commercial production, in particular, during the synthesis of detergents, can be produced by the interaction of the a-olefins of the unsaturated hydrocarbon fractions Cg-Cjg (olefin content no less that 97 wt%) and 98% sulfuric acid at the ratio of a-olefin/H2S04 = 1/1.2-1.4 mole, with further neutralisation of the imreacted H2SO4 and saponification of the synthesised alkyl sulfur acid ... 

According to the final product, leather requires a certain softness, which is achieved by application of fat. A fat content of 5% is essential gloves, garments, and upholstery may contain up to 15%. Therefore, after dyeing, the leather is oiled. In this process, called fatliquoring, oily fat is emulsified and applied to the leather in a warm bath. The emulsion breaks on contact with the chrome-tanned fibers of the leather, and the fat remains on the leather. The oils used are sulfated or sulfonated plant, animal or fish oils or synthetic products, usually biocide preserved (Heidemann 1990 Podmore 1995 Thorstensen 1995). 

The synthesis by route C is an alcoholysis reaction. The reaction proceeds as an emulsion due to the immiscibility of triacylglycerol and glycerol. Under this emulsified condition, the equilibrium concentration of the monoacylglycerol is 30% (Yamane et al., 1986). However, when the reaction is run at temperatures slightly below the melting point of the fat used, the concentration is favourably increased to 70-90% (McNeill et al., 1990 McNeill and Yamane, 1991). The reaction rate is affected by moisture content. Relatively high moisture leads to high initial reaction rates (McNeill et al., 1991) but excessive levels result in hydrolysis and production of free fatty acids. Compared to the synthetic pathways of A and B, route C seems a cheaper alternative since the primary reactive components do not include free fatty acids reactants that otherwise would have to be produced by other methods to make them available for the process. 

Emulsion-based adhesives are adhesives that contain aqueous synthetic resin dispersions or emulsions or rubber latices as their principal raw material or active binder [41]. They are milky white, odorless hquids with solids contents of 40 - 60 %. In quantitative terms, emulsion-based adhesives are one of the most important groups of adhesives. They set by the release of water and the formation of a film fi om the emulsified or dispersed resin or rubber droplets. 

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