CHEM208 - Module 6
What is involved in the hair coloring process?
1. The bleach oxidizes the melanin molecules in hair. This oxidized molecule is colorless (irreversible). The occasional yellow color is from keratin which is it's natural color. Hydrogen peroxide is one of the most common lightening agents. The peroxide is used in an alkaline solution which opens the hair shaft to allow the peroxide to react with the melanin. 2. Ammonia is the alkaline chemical that opens the cuticle and allows the hair color to penetrate the cortex of the hair. As the melanin is de-colorized, the new color bonds to the hair cortex. 3. Conditioners close the cuticle and seal the hair to protect the new color.
What are some of the major developments in the field of hair coloring?
-large variety of colors -Improved delivery systems to enhance the adhesion of colors to the hair. -More effective conditioners to neutralize the harsh effects of dye chemicals.
List the steps in the soap/detergent chemical interaction.
1. Chemical interaction with soap or detergent traps the oily and greasy soil molecules. In aqueous solution, surfactants cluster near the surface. 2. The hydrophobic tails are attracted to grease and the hydrophilic heads to the water, thereby forcing the grease away from the soiled surface. 3. The grease is then surrounded by the individual surfactant molecules and removed from the soiled surface.
Explain the three steps in hair curling;
1. Treatment of hair with a reducing agent (an electron donor) that breaks certain covalent bonds. 2. Setting hair in the desired shape 3. Treating hair with an oxidizing agent (an electron acceptor) such as dilute solution of hydrogen peroxide to reform the previously broken covalent bonds in the new shape.
What are surfactants composed of?
A hydrophilic (water-soluble) head and a hydrophobic (fat-soluble, water-hating) tail. The hydrophilic end is stable when solubilized in water and the hydrophobic end consists of a long chain hydrocarbon that is more stable when surrounded by other organic groups.
What is an oxidizing agent?
A substance that oxidizes (i.e., accepts electrons) another substance in a chemical reaction and in turn gets reduced (i.e., donates electrons).
What is a Reducing agent?
A substance that reduces (i.e., donates electrons) to another substance and in turn gets oxidized (i.e., accepts electrons).
What is used in order to reduce damage to the hair during the coloring process?
Ammonia has been replaced by ammonium carbonate.
What is an alkali?
An alkali is a soluble salt of an alkali metal like sodium or potassium. Originally, the alkalis used in soapmaking were obtained from the ashes of plants, but they are now made commercially. Today, the term alkali describes a substance that chemically is a base (the opposite of an acid) and that reacts with and neutralizes an acid. The common alkalis used in soapmaking are sodium hydroxide (NaOH), also called caustic soda; and potassium 07Chemhydroxide (KOH), also called caustic potash.
What class of surfactants are detergents?
Anionic Surfactants and Nonionic. Anionic; The chemical reacts with hydrocarbons derived from petroleum or fats and oils to produce new acids similar to fatty acids. A second reaction adds an alkali to the new acids to produce one type of anionic surfactant molecule. Nonionic Surfactants Nonionic surfactant molecules are produced by first converting the hydrocarbon to an alcohol and then reacting the fatty alcohol with ethylene oxide.
What category of surfactants is soap?
Anionic.
Expand on deodorants
Body odors are reduced or masked by the use of deodorants. Such odors may originate from the conversion of certain compounds (present in the perspiration) to unpleasant odors by bacteria. Thus the effective chemical ingredients in such products are antibacterial agents and perfumes.
What are the three interactions found in the cleaning process?
Chemical, thermal and mechanical interactions, which take place in the overall process of cleaning.
What are alpha-hydroxy acids classified as?
Cosmeceuticals
What are fragrant compounds?
Create fragrances for perfumes. These are blended alcoholic solutions of various ingredients whose fragrances are usually experienced in three distinct notes.
Summarize hair curling;
Curling of hair involves more complex chemistry, as covalent bonds are first broken (using a reducing agent) and then reformed (using an oxidizing agent) in the new shape.
How do deodorants work?
Deodorants contain antibacterial agents that kill the bacteria responsible for converting certain compounds in perspiration into unpleasant odours
How did detergents form?
Detergent surfactants were developed in response to a shortage of animal and vegetable fats and oils during World War I and World War II. In addition, a substance that was resistant to hard water was needed to make cleaning more effective. At that time, petroleum was found to be a plentiful source for the manufacture of these surfactants. Today, detergent surfactants are made from a variety of petrochemicals (derived from petroleum) and/or oleochemicals (derived from fats and oils).
Emollients
Emollients provide some occlusivity and improve the appearance of the skin by smoothing flaky skin cells. There are many different types of emollient esters and oils available to a formulation chemist. 3,4 Emollients are generally grouped by their ability to spread on the skin. By combining emollients with the different spread rates you can tailor the skin feel of a moisturizer. You can test for these differences by using different emollients in a standard base lotion. Additionally, emollient lipids similar to those naturally found in the skin may also increase the rate of barrier repair.
Expand on cosmetics
Facial cosmetics such as lipstick and mascara generally contain oils, waxes, pigments and perfumes. Lipstick manufacturers blend various proportions of oils, waxes and emollients (to soothe the skin) to formulate the base for their unique brand. Fragrances, pigments, preservatives, antioxidants and a variety of other ingredients are then added.
Explain the three notes in perfumes.
Fragrances in perfumes are generally experienced in three different stages referred to as top, middle and base notes. The top notes are the most volatile components and hence experienced immediately after the opening of the package. The middle notes are experienced next followed by the base notes which last longest.
What is the oxidizing agent generally used during hair curling?
H2O2 (hydrogen peroxide)
What are the active ingredients in skin moisturizers?
Humectants Emollients Occlusive agents.
Humectants
Humectants include ingredients like glycerin, urea, and pyrrolidone carboxylic acid (PCA). Humectants work by attracting water from the dermis below and helping to keep that water bound in the stratum corneum. Glycerin is used frequently because of its low cost and high efficacy, but a tacky feel on the skin is one of the drawbacks of formulating with high levels of humectants. When optimizing skin formulations, cosmetic chemists try to reduce these negative properties of humectants.
What are the two types of active ingredients commonly used in sunscreens classified as?
Inorganic; Approved for use are titanium dioxide and zinc oxide. These work primarily by reflecting and scattering UV light. Organic: Wide varieties are approved for use. These work primarily by absorbing UV light and dissipating it as heat.
How do you determine the effectiveness of a sunscreen?
It's formulation is rated by its ability to block UV-B rays that cause skin burns. It is called Sunburn Protection Factor (SPF).
Is it true that detergents are made from animal fat and wood ash?
Nope.
Occlusive agents
Occlusive agents increase moisture levels by providing a physical barrier to epidermal water loss. Ingredients with occlusive properties include petrolatum, waxes, oils, and silicones. Some occlusive agents like petrolatum can leave a heavy feel so they are often combined with other ingredients, like emollients, to improve consumer appeal.
What does PABA stand for?
Para-aminobenzoic acid
In the cleaning process, the polar end of the surfactant is attracted to water because water is...
Polar.
What else do surfactants do?
Surfactants perform other important functions in cleaning, such as loosening, emulsifying sinkdishes(dispersing in water) and holding soil in suspension until it can be rinsed away. Surfactants can also provide alkalinity, which is useful in removing acidic soils.
What is the SDSI?
The Safer Detergent Stewardship Initiative (SDSI) program of the U.S. Environmental Protection Agency (EPA) recognizes corporate environmental leaders using safer surfactants which break down quickly into non-polluting chemicals and thus protect aquatic life.
How are ingredients blended in perfumes?
The ingredients are blended based on their molecular size and volatility.
What are surfactants?
These water-soluble surface-active agents are used to reduce the surface tension of water. They are responsible for the chemical interactions, trapping the oily and greasy soil molecules.
How are the classes of surfactants determined?
They are categorized by the charge of the hydrophilic component of the surfactant molecule after dissociation in water.
What are examples of some cosmeceuticals that are only available with a doctor's prescription?
They include, among others, Botox (for a more youthful look), Vaniqa (to eliminate unwanted facial hair) and Propecia (for bald men).
What do surfactants do to water?
This reduction in surface tension makes water easier to spread. Thus making it an effective cleaning process.
Why is water hard?
Water containing high concentrations of the divalent alkaline earth metal cations calcium (Ca2+) and magnesium (Mg2+).
What are cosmeceuticals?
certain cosmetics--which contains ingredients that may act like pharmaceutical.
In aqueous solutions, surfactants...
cluster near the surface.
Laundry detergents are formulated by mixing many ingredients in order to...
perform diverse functions.
A cationic surfactant has what charge?
positively charged.
What are some influencing factors on personal care products?
• Aging population • Changing attitudes of men • More women in the workplace • Concerns about exposure to ultraviolet radiation
What are the classes of surfactants?
• Anionic surfactants have a negative charge. • Cationic surfactants have a positive charge. • Non-ionic surfactants have no charge. • Amphoteric surfactants have both positive and negative charges.
What are some of the environmental trends in consumer cleaning products?
• Contain surface protectors or modifiers that repel soil and stains more effectively. • Deliver active ingredients in a controlled way. • Are effective in cold water. • Contain natural or naturally derived ingredient(s). • Do not contain chemicals of concern with respect to toxicity. • Generate less carbon dioxide during production (smaller environmental footprint).
What are disadvantages of soap? (3)
• Formation of soap film (or scum) in water. The calcium and magnesium ions react with soap molecules to produce calcium and magnesium salts of fatty acids. These salts are insoluble in water and impair the surfactant properties of soap because the amount of soap available for cleaning is reduced. Soap scum is difficult to rinse away and can be visible, i.e., on fabrics, bathtubs and sinks. • Poor adaptability to diversity of fibers, washing temperatures and water conditions. • Tendency to clog sewage systems due to their gelling properties.
What are soaps and detergents composed of?
• Soaps and detergents are composed of surfactants. • Surfactants are water-soluble and surface-active agents
What are the advantages of soap? (2)
• Soaps are manufactured from combinations of natural and renewable resources. • Soaps are biodegradable and thus do not pollute bodies of water
What chemicals are laundry detergents formulated from?
• Surfactants to bind and suspend grease and dirt in the washing water • Builders to remove Ca2+ and Mg2+ from hard water and soil • Bleaching agents to remove stains and kill bacteria • Enzymes to catalyze the degradation and elimination of some stains • Miscellaneous chemicals such as foam stabilizers, fabric brighteners, fragrances, corrosion inhibitors etc. are added in small quantities.
What are the factors that determine the protection duration of a sunscreen?
-Activities (swimming or exercise) -Amount applied and frequency of reapplication -Solar intensity -Type of skin -Amount of sunscreen absorbed by the skin
What is an AHA and how do AHA's work?
-Alpha hydroxy acids (AHAs) became important ingredient in many cosmetic formulations claiming to reduce signs of aging, sun-damaged skin and wrinkles. These work by breaking down and lifting off part of the top layer of dead skin cells in order to get rid of some surface damage and accelerate growth of living cells
In addition to the dye found in hair dye, what other constituents make up hair dye?
-Ammonia, hydrogen peroxide and a surfactant.
What type of surfactant is soap? Explain it's chemical composition;
-Anionic Surfactant -Consists of the long hydrocarbon tails of fatty acids and the polar heads of sodium or potassium salts of fatty acids (found in fats and oils of animals and plants). -Soaps are water soluble sodium or potassium salts of fatty acids. They are then treated chemically with strong alkali.
Explain Conditioners
-Conditioners usually contain cationic surfactants. -These help in rinsing out any residual shampoo and at the same time provide softer and easy to manage hair.
What can exposure to UV radiation cause?
-Painful sunburns -Damage to skin -Skin cancer
What can soaps/detergents be classified to be used for?
-Personal hygiene -Laundry -Dishwashing -Household cleaning
What functions do moisturizers perform?
-Prevent and treat dry skin -Protect skin -Make it appear smooth by encouraging an orderly shedding process. -Improve skin tone and texture -Protect sensitive skin and mask imperfections.
How do sunscreens work?
-Protect the skin against UV radiation. -UV radiation emitted by the sun consists of UV-A and UV-B rays. -Sunscreen have additional chemical ingredients that absorb UV radiation
Explain Shampoo
-Shampoos are cleansing agents containing anionic surfactants to remove oil and dirt from the hair and scalp. -Surfactants produce foam, lifting the oil and dirt from the hair. -Fragrances, thickeners, foam boosters and other agents may also be added.
What layer is responsible for destroying UV Radiation?
-Stratospheric ozone layer.
How do moisturizers work?
-They are used to increase the water content of the skin.