Australia

Cosmetic Chemistry

History of c osmetics The tombs of ancient Egypt have revealed that cosmetic paints were used as far back as 5000BC. Eyes were decorated with black galena paste and painted green with malachite ore. In Roman times women wore rouge and lip balm and their hair was treated with henna. It was during this time that a Greek physician made the first cosmetic emulsion by adding rosewater to molten beeswax and olive oil. The Babylonians used pumice stone to whiten and smooth their skin. During the reign of Queen Elizabeth I, face powder contained lead carbonate, powdered marble, borax and starch to whiten skin, with costly results.

The word ‘cosmetic’ derives from the Greek word kosmeticos which means improvement to one’s beauty.

What is a cosmetic today?In today’s world we use cosmetics to cleanse, perfume, protect and change the appearance of our bodies.

The Australian Trade Practices Act 1974 defines a cosmetic as ‘a substance or preparation intended for placement in contact with any external part of the human body’ (this includes the mouth and teeth). Products that ‘modify a bodily process or prevent, diagnose, cure or alleviate any disease ailment or defect’ are called therapeutics. This means that deodorants and shampoos are called cosmetics while antiperspirants and anti-dandruff shampoos are considered to be therapeutics.

EmulsionsAn emulsion consists of tiny droplets of one liquid suspended (not dissolved) in another. There are two types of emulsions and both are used widely in the production of cosmetics. To keep emulsions stable an emulsifier must be present. Emulsifiers are bridging molecules which bridge the gap between the water and oil. They insert their hydrophobic tails in the oil molecule and their hydrophilic heads in the water molecules.

Oil in Water (O/W) emulsions are made up of oil (disperse phase) dispersed as droplets throughout water (continuous phase). They feel cool on the skin because the water base can evaporate easily. As the water evaporates, the oil remains as a thin film on the skin. This is called a residual film. Oil in water emulsions, such as hand creams, face cleansers and conditioners are used to moisturize or protect the skin and hair by placing oil onto the surface. They have a lubricating effect and provide sheen. If a small amount is placed into water and shaken or stirred it will remain suspended.

Water in Oil (W/O) emulsions are made up of water (disperse phase) dispersed as droplets throughout oil (continuous phase). They feel greasy on the skin because the water cannot evaporate as rapidly. Water in oil emulsions, such as night creams and hair creams, are useful to cleanse the skin, moisturize very dry skin and hold hair in place, but are greasy and sticky to the touch. If a small amount is placed into water the emulsion will not be maintained. This emulsion is used when the cosmetic needs to coat the skin with a layer of colour eg foundation, lipstick, blusher, eye shadow and mascara.

Hand Cream

Introduction

Hand cream has two phases: an oil mix and a water mix.

Oil Mix

1) Vegetable oil, eg. sweet almond oil.2) Emulsifier, eg. Emulsifying pearls.

An emulsifier is a substance included in a mixture which ensures that oil and water mixtures do not separate into layers.

Water mix

1) Vegetable glycerine.2) Water (floral waters can be used).

Materials

10 ml sweet almond oil

6 g emulsifying pearls

50 ml water

6 ml vegetable glycerine

5 drops wheat germ oil or vitamin E oil

2 drops essential oil

Method

1) Place 10 ml of sweet almond oil and 6 g emulsifying pearls into a 100 ml beaker.2) Heat the sweet almond oil and emulsifying pearls until the pearls have melted.3) Place 50 ml water and 6 ml of glycerine into a 100ml beaker.4) Heat the water and glycerine until just below boiling.5) Add the water and glycerine mix to the oil mix and stir well until completely blended.6) When cool add 5 drops of wheat germ or vitamin E oil as a preservative and stir.7) Add 2 drops of your chosen essential oil and stir in well.8) Pour into a small sterile glass jar.9) Add label if required.

Chemistry of Bath BombsBath bombs contain a base – sodium bicarbonate and an acid – citric acid. When the acid and base come in contact with water a chemical reaction occurs and carbon dioxide gas is produced. This gas is seen as lots of tiny bubbles.

The following chemical equation shows the reaction between citric acid and sodium bicarbonate.

Reactants Products

Citric Acid + Sodium Bicarbonate Carbon dioxide + Water + Monosodium Citrate

H3C6H5O7 + NaHCO3 CO2 + H2O + NaH2C6H5O7

When a weak acid and a weak base neutralise each other, the products of the reaction always include water and a salt. Salts are everywhere, the most common being sodium chloride, NaCl, or common salt. Nearly all salts dissolve in water to a certain extent. Sodium bicarbonate is used to absorb moisture and odours, so an open box can be left in a refrigerator for this purpose. A paste form of sodium bicarbonate can be very effective when used in cleaning. When used in toothpaste, sodium bicarbonate helps to gently remove stains, whitens teeth, freshen breath and dissolves plaque. Sodium bicarbonate is also used as a fire suppressing agent in some dry powder fire extinguishers.

Making Bath Bombs

Materials

32 g (4 tbs) Bicarbonate soda Plastic cup

16 g (2 tbs) Citric acid Icy pole stick

2 drops Food colouring Tea strainer

2 drops Essential oil Witch Hazel spray

Method

1) Sieve the bicarbonate soda and citric acid together into a paper cup.2) Add food colouring and essential oil.3) Mix all these ingredients together well with an icy pole stick.4) Give a light spray (3 -4 squirts) with witch hazel and mix well.5) Press into a mould. 6) Turn out onto paper on a white tile. Can be placed in a low oven to dry.7) Package and label.8) Other tests:

Does the temperature of the water the bath bombs are placed in change the reaction.How does the pH fluctuate during the reaction?What happens if you change the ratios of citric acid and sodium bicarbonate?

Bath Milk Bundles

Materials

1 teaspoon Epsom salts 1 teaspoon Citric acid

1 teaspoon Coconut or full cream milk powder 5 drops Essential oil

1 teaspoon Bicarbonate soda Plastic cup

1 teaspoon Oats or bran Icy pole stick

Method

1) Mix all the ingredients together in a plastic cup with an icy pole stick.2) Add 5 drops of your chosen essential oil and continue to mix well.3) Place into the middle of the fabric circle and close with an elastic band.4) Finish off with a piece of ribbon and label.

Bath Salts Tea Bags

Materials

25 g (3 tbs) Epsom salts

8 g (1tbs) Bicarbonate soda 5 drops Essential oil

25 g (3 tbs) Rock salt Plastic cup

8 g (1 tbs) Tartaric acid Icy pole stick

Method

1) Mix all the ingredients together in a plastic cup with an icy pole stick.2) Add 5 drops of your chosen essential oil and continue to mix well.3) Rose petals or lavender flowers may be added for special effect.4) Place into the prepared teabag. Staple closed and attach the tag.

Soapy Science

History of Soap

Soap berries and the bulb of the soap plant which both contain saponin have been used for centuries as a cleaning agent. Originally soap was made by pouring hot water over wood ash to make an alkali (potash) and this was boiled with animal fat to produce soap. It was very harsh and also had a very bad odour. Soap was still a luxury in the time of Queen Elizabeth 1, who reported to have ‘had a bath every three months whether she needed it or not’. In Australia soap was first made in homes but it was too harsh for personal use, so it was only used to wash clothes. Eventually soap was produced commercially in the late 19th century with perfumes and anti bacterials for personal use.

Soap and Saponification

Soap is made by fats and oils reacting with lye. The origin of the fats and oils may be animal or vegetable and the lye may be caustic soda (sodium hydroxide) or caustic potash (potassium hydroxide). The chemical reaction is called saponification.

Coconut Oil (stearic acid + glycerol) + caustic soda = soap (sodium stearate) + glycerine (glycerol)

Manufacturers add perfumes to give their soaps a pleasant smell. Many also add chemicals to make the soap lather and to kill harmful germs that can live on skin.

How does soap remove grease and oil?

Soap cleans by the use of surfactants (surface active agents). These molecules have both fat soluble (lipophilic) and water soluble (hydrophilic) parts. The lipophilic part of the molecule sticks to oil and dirt, and the hydrophilic part allows water to remove the water insoluble grime. Soap is an excellent cleanser because of its ability to act as an emulsifying agent. An emulsifier is capable of dispersing one liquid into another liquid. This means that while oil (which attracts dirt) doesn’t naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed.

Natural Soap

Introduction

Ecol soap powder is a natural soap which contains no perfumes, dyes, petrochemicals or additives, and is free from alkalis. It is totally vegetarian which makes it allergy free and safe on sensitive skin. Ecol soap will break down immediately and completely in the environment, making it totally biodegradable (capable of being broken down by the action of living things).

Materials

60 g (1 scoop) Ecol soap powder

25 ml (3 tbs) Water

2 drops Food colouring

2 drops Essential oil

10 ml (1 tbs) Sweet almond oil

Plastic cup Icy pole stick

Method

1) Mix all the ingredients together in a plastic cup with an icy pole stick.2) Remove mixture and knead well with the hands until smooth and lump free.3) Add small amounts of water if needed.4) Press into a mould or make into a ball or bar with your hands.5) Leave to dry for 24 – 48 hours.6) Package and label.

Cool Cold Cream

Introduction

Cold creams have been used for thousands of years to clean the skin and remove unwanted make-up. They are relatively inexpensive and easy to make.

Materials

13 g Beeswax Hotplate

50 ml Liquid paraffin 100 ml Measuring cylinder

33 ml Water Balance

1 g Borax Stirring rod

Thermometer 100 ml beakers X 2

Method

1) In beaker A, heat the beeswax and paraffin oil gently, stirring continuously, until the beeswax melts and it reaches 70 C.

2) In beaker B, heat the water and borax, stirring continuously, until the borax has dissolved and the solution reaches 70 C.

3) When both solutions are hot enough add beaker B to beaker A and stir.4) Allow to cool before pouring into a sterile jar.5) When cold cream has set, apply some make-up to your hand and then use the cold

cream to clean the skin. Apply make-up to another part of the skin and try to wash it off with soap and water.

Body Scrubs

Lavender Body Scrub

2 tablespoons Polenta

2 tablespoons Clay

2 drops Citrus seed extract

5 drops Lavender oil

1 teaspoon Honey

2 tablespoons Lavender water

1) Mix polenta with the clay.2) Add water and mix to a paste.3) Add honey, citrus seed extract and lavender oil and mix thoroughly.

Natural Lip BalmLip balms protect and soften the skin on your lips. Natural lip balms contain pure products rather than mineral oils and petrochemicals. Pure essential oils added to the lip balm add healing and antiseptic properties. Essential oils suitable for the sensitive skin of lips include lime, mandarin, orange peppermint, sandalwood and spearmint.

Materials

15 g (5 tsp) Beeswax 5 g (1 tsp) Cocoa butter

80 ml (10 tbs) Sweet almond or jojoba oil 6 ml (1 tbs) Vegetable glycerine

20 drops Essential oil

Method

1) Melt the beeswax and cocoa butter over a water bath.2) Add the oil and glycerine and heat until all melted.3) Remove from heat and use an electric blender to disperse all ingredients evenly.4) When the mixture begins to cool, stir in the essential oils and the honey.5) Pour into small lip balm containers.

Tasty Toothpaste

Materials

Water Dropper

Calcium carbonate Icy pole stick

Sodium bicarbonate Plastic cup

Vegetable glycerine Peppermint essential oil

Method

1) Place ½ teaspoon calcium carbonate and ¼ teaspoon of sodium bicarbonate into a plastic cup.

2) Add 1 teaspoon of glycerine and enough drops of water to make a paste.3) Add 2 drops of Peppermint essential oil and mix well.4) Further discussion:

How to make the product more ‘marketable’ by adding colours, flavours or sweeteners.Why does toothpaste have to be mildly abrasive as well as cleansing?

10 Most Asked Questions

1. Where do I get all the requirements from?Supermarket and Auroma ( www.auroma.com.au)

2. What material do I use to make the Bath Salt Teabag?Light weight Iron on Vilene from a fabric store.Tags from an office supplier.

3. What size do I cut the Vilene?26.5 cm X 8 cm and iron down each side.

4. What can I use to colour the soap if I don’t use food dyes?Coloured clays work well and are therapeutic.

5. What do I use as an antibacterial and antifungal?Grapefruit seed extract, Vitamin e oil or wheatgerm oil.

6. How do I make my bath bomb mixture stay together?The trick is the light spray of witch hazel to start the chemical reaction.

7. What is an alternative for Calcium Carbonate in the toothpaste recipe?Try ground up indigestion tablets that contain Calcium Carbonate.

8. How can I make the hand cream light and aerated?Use a kitchen wizz or bamix.

9. What can I use as a soap mould?Well washed milk cartons, Pringles containers, chocolate moulds, and fabric petals for melt and pour soaps.

10. What is the best recipe book? Do It Yourself Pure Plant Skin Care by Carolyn Stubbin