الفئة المستهدفة : طالبات جامعة
الوسيلة : مناقشة وتطبيق عملي
مدة المحاضرة ساعة ونصف
تعريفات هامة .. (نصف ساعة )
shampoo : preparation of surfactant in a suitable form (liq. , gas , or powder)
uses of shampoo :
remove sebum , surface grease , dirts & atmospheric pollutants from hair
make the hair soft &easy to comp
Surfactants
Like emulsifiers, surfactants (abbreviation of SURFace ACTive Agents) are compounds ableto mix oils and water. Their cleansing effect is from the skin in a watery environment. Basedon the cleansing and foaming property surfactants are dvided into primary and secondary surfactants (secondary surfactants are also
called co-surfactants). The primary surfactants are the key components in shampoos responsible for foam and cleansing. The low-foaming co-surfactants as cocoamidopropyl betaine or sulfosuccinate are used to reduce the irritant (eye burning) and drying effect of the primary surfactants. In addition, some co-surfactants have also conditioning effects like the betaines. Thus, a blend of a primary and secondary surfactant and water is the backbone of a every shampoo .
Conditioners
Nowadays practically all shampoos contain a conditioner of some type. Consumers expect that their hair is smooth and conditioned after shampooing. Most often conditioning agents are quaternary surfactants (quats) which possess a positive charge that neutralize static electricity caused by negatively charged damaged hair cuticles. Quats also have fatty groups improving wet comb and gloss.
Thickeners
Nobody wants to use a water-thin shampoo (although they would work as well as thick ones). Thickness is perceived as “richness”. There are several ways to make a shampoo thick. Very effective viscosity enhancers are salts like simple table salt (sodium chloride) or ammonium chloride which work, however, only with sulfonates or sulfates. Note, too high an amount of salts make a shampoo more harsh.
Other effective thickeners are gums including guar, xanthan and cellulose gum which increase viscosity by forming kind of a gel.
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