Surfactants and Suspending Agents

Approximations can be made to estimate how much surfactant is needed to maintain a desired dispersion. This is illustrated by example. 

Example 12.2. Suppose that a dispersion is to be 50% oil dispersed in water and consist of 50 p,m drops. The surfactant molecular weight is 350. Assume that the molecular dimensions of the surfactant are 4 A x 7 A and that drop stability is obtained when surfaces are 50% covered. Estimate the surfactant requirement. 

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U.S. 4728457 (1988) Fieler (Procter Gamble) Heated premixes (silicone) are added to a main mix (surfactants and suspending agents) at ambient temperature Improved process for making silicone-containing shampoos... 

Fedina, L. T., R. Zelko, L. I. Fedina, Z. S. Szabados, M. Szanto, and G. Vakulya. 1997. The effect of surfactant and suspending agent concentration on the effective particle size of metered-dose inhalers. /. Pharm. Pharmacol. 49 1175-1177. 

Uses Granulation binder In pharmaceutical controlled release hydrophilic matrix systems and controlled release coatings viscosity modifier, surfactant, and suspending agent In pharmaceutical llq. systems Regulatory USP, EP, kosher... 

Soprophor . [Rhone-Poulenc Surf. Rhone-Poulenc Geronazzo SpA] Al-koxylated alcohols, EO/PO block polymers, sulfonates, m edioxylates surfactant wetting and suspending agents for degreasers, acid pidding conqxls., pesticides. 

Uses Pigment dispersant and suspending agent, wetting and grinding aid for oil-based paint systems surfactant for latex paints. Witcobond A-100 [UniroyaQ... 

Function in Formula Carbopol 1342 and 1382 resins are thickening/gelling and suspending agents for surfactant systems Pemulen TR-1 and TR-2 resins are primary emulsifiers for lotions and creams... 

Detergent, foaming and suspending agent. Produces copious rich foam. Primary surfactant in liquid, hard-surface cleaners carpet shampoos upholstery shampoos and spot removers. Good viscosity response to the additions of salt and alkanolamides. SULFOCHEM SLX ... 

The first successful aqueous polymerization of vi-nylidene fluoride was reported in 1948 [83] using a peroxide initiator in water at 50-150°C and 30 MPa. No surfactants or suspending agents were present in the polymerization recipe. PVDF has been polymerized by a number of methods including emulsion, suspension, solution, and bulk. Later, copolymers of vinylidene fluoride with ethylene and halogenated ethylene monomers were also produced [84]. In 1960, a manufacturing process was developed and PVDF was introduced to the market. 

Uses Surfactant, mild detergent for use In low pH systems foaming and suspending agent for personal care and Industrial applies. 

Many polymerizations are carried out in heterogeneous media, usually water-monomer mixtures, where suspending agents or surfactants ensure proper dispersion of the monomer and control the particle size of the product. 

In a multiphase formulation, such as an oil-in-water emulsion, preservative molecules will distribute themselves in an unstable equilibrium between the bulk aqueous phase and (i) the oil phase by partition, (ii) the surfactant micelles by solubilization, (iii) polymeric suspending agents and other solutes by competitive displacement of water of solvation, (iv) particulate and container surfaces by adsorption and, (v) any microorganisms present. Generally, the overall preservative efficiency can be related to the small proportion of preservative molecules remaining unbound in the bulk aqueous phase, although as this becomes depleted some slow re-equilibration between the components can be anticipated. The loss of neutral molecules into oil and micellar phases may be favoured over ionized species, although considerable variation in distribution is found between different systems. 

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