Silicones, surfactants for

Silicone surfactants. For the purpose of this work, silicone surfactants will be defined as silicone polyether copolymers with hydrolytically stable silicon-carbon bonds. The manufacturing of these products involves a three-step process ... 

Most elements have NMR-active nuclei, i.e., nuclei possessing a magnetic moment. For surfactant systems, the situation is very good in that H and C nuclei, which occur in most surfactant molecules, have good NMR properties. For relaxation work, however, it is often advantageous to use NMR on selectively deuterated compounds. F NMR is very useful for the study of fluorocarbon surfactants, P NMR for phospholipids, and Si NMR for silicon surfactants. For studies of water molecules we have a choice between three good alternatives H, H, and NMR. Many common counterions, e.g., Na, Li, Rb, Cs, F, Cl, Br, and I, have highly sensitive nuclei, whereas others, such as K" ", Mg " ", Ca ", and SO ", have lower sensitivity and are more difficult to study. 

Not taking cyclic molecules into account, the general structures of industrial silicone surfactants for flexible slabstock foam production can be seen in Figure 2.13. The main building blocks of these materials are a PDMS backbone and attached polyethers based on ethylene oxide and propylene oxide addition products. The siloxane backbones can either be linear or branched and can have their polyether substituents attached in an either pendant or terminal location. These four general structures are outlined in Figure 2.13). 

Non-hydrolysable silicone surfactants (for Asian PU foam producers) are Dabco DC2583 and DCS 188, respectively reducing surface skin and producing open-cell foam at low mould temperatures, and producing fine even-cell structure and improved emulsification in flexible slabstock systems. 

Figure 6a and c show typical structures of silicone surfactants for the production of polyurethane foam, i.e., comb-like and branched siloxanes. Siloxanes that are modified with polyether groups are important surfactants for rigid, ester, or flexible slabstock foams. 

Uses Emulsifier, suspending agent for triglycerides, min. oil, and silicones surfactant for pharmaceuticals and personal care Properties Amber waxy flake insol. in water... 

Uses Silicone surfactant for PU shoe systems and other microcellular foams Features Not hazardous... 

Uses Silicone surfactant for flexible PU Features Not hazardous does not contain aminic components Properties Cl., colorless to si. yel. liq. misc. with water dens. 1.01-1.03 kg/m vise. 550-1100 mPa-s flash pt. > 100 C ref. index 1.444-1.449 turbidity pt. = 29 C... 

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