|MadSci Network: Chemistry|
Actually there is a very simple way to thicken soap products. First, to one cup warm water mix as much salt as you can get into solution. Second, drain the solution and separate any remaining salt. Third, very slowly mix about a teaspoon of the salt water into 1 quart of soap. Continue step three until the solution begins to thin again. What is happening? Salt loves water and will attrack water from the soap solution to hydrate itself. As the water is removed from the soap, it begins to thicken. Why does the soap begin to thin when too much salt is added? As you remove more and more water from the soap, a second solution phase will form that is mostly salt water. This will make the soap phase non-continuous and very unattractive. Another possible solution is too heat the soap up to about 150 degrees F and very slowly sprinkle starch onto the top of the soap. Mix this thoroughly. Here again too much will turn the soap into a very unattractive mess. A third possibility (and I haven't tried this one) is gelatin. It will probably work, but will be more expensive than the first two. [Editors Note: Shampoo can also be thickened by addition of a water soluble polymer such as methyl cellulose, carboxymethyl cellulose or high molecular weight polymers of ethylene oxide. You won't find these names on a shampoo bottle, however, because they sound too much like "chemicals". The Cosmetic, Toiletry and Fragrance Association [CTFA] has devised a set of 'user friendly' names for these ingredients. They publish a dictionary that translates the label name into the real chemical name, but it is not readily available to the public, i.e., members only. Ken Johnsen MADSci Administration]
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