OMG!CHEMISTRY'saroundME!!

Wednesday, July 1, 2009 deodorants = body odour

When we see a deodorant bottle, automatically 1 thing that
will just pop out from our head, that is body odour.

Body odour is never pleasant, and we've all been crammed on
a train or been in crowded places and noticed the distinctive smell
of stale sweat from even your own friends sitting next to you in class.

How and why body odour existed? Why??

Everybody sweats. We have to. Perspiration is the body's biological
way of cooling down.

Sweat itself does not smell, but it is a “wonderful” culture for the bacteria
that live on our skin. Woahh!! We have homes for bacteria! We’re cool
humans after all.

The bacteria break down sweat into aromatic fatty acids, which
produce the unpleasant odour. So, the cause of body odour is not
from the sweat itself.

Then, deodorants exist to overcome the body odour. Thank you to the person who created deodorants.

Now, the common ingredients in a deodorant are as below.

Perfume & skin conditioners

Perfumes and fragrances are used in most deodorants to
mask body odour and provide a feeling of freshness to the user.
Virtually all deodorant products will contain some emollient oils
to sooth and soften the skin by preventing water loss.
The moisturizers used in deodorants are usually glycerin or
vegetable derived oils, such as Helianthus Annuus (a sunflower oil).
Most deodorants will also contain masking oil to stop the product
drying out into deposits, thus minimizing what shows up on either skin or clothes.

The active ingredients of deodorants are often dissolved in alcohol
because it dries quickly once applied to the skin and gives an
immediate sense of coolness. Thus, alcohol is a common ingredient
in many roll-ons, aerosol deodorants and some gels.
Skin that has been sweating will sometimes have quite a greasy feel to it.
Silica is a natural mineral which is often used in deodorants to
mop up this oiliness so that users no longer feel the greasy after-effects of sweat.

Some deodorant products also include an ingredient called PEG-8 Distearate
which makes it easier to wash the product off in the bath or
shower at the end of the day.

Salts
Depending on the type of product, deodorants usually contain salts
to actually reduce the flow of sweat from the skin. These salts work
by dissolving in sweat and leaving a thin coating of gel over the sweat glands.
This coating reduces the amount of sweat on the skin for a number of
hours after the antiperspirant is applied. Aerosol and roll-on products
will most likely contain ACH (Aluminium Chlorohydrate), whereas sticks, gels
and other solid products are most likely to contain deodorant salt called
AZAG (Aluminium zirconium tetrachlorohydrex GLY).
These salts provide the safest and most effective means of controlling sweat.

Some people may be concerned about the use of aluminium in
deodorants believing that it can damage health. For example, it has
been suggested that aluminium is a possible contributory factor for
Alzheimer's disease. However, experts and research bodies
including the Alzheimer's Society say there is no relationship
between the two. In 2003 the U.S. Food and Drugs Administration
published a major study which concluded that deodorants and their aluminium salts are safe.

Carriers & structurants
In order for deodorants to be effectively applied to the skin, they
need to be held in some kind of carrying structure whether that be
the liquids used in aerosols or the solids used in sticks.

Water is used in a range of deodorants as a carrier for other ingredients.
It adds fluidity to products like roll-ons and creams and helps the
product spread onto the skin. In aerosol products the active ingredients
are contained in a neutral liquid which enables them to be easily sprayed
onto the skin. This liquid (the most popular of which is cyclomethicone)
is often combined with slightly denser clay called disteardimonium hectorite
which provides structure to the deodorant and stops heavier
particles sinking to the bottom.

In the same way that aerosols are transported via a carrier fluid,
other more solid products need an agent which will provide structure
and prevent the other ingredients from separating out.
This structure can be provided by a combination of ingredients
including Hydrogenated Castor Oil, 18-36 Acid Trygliceride, Stearath or Stearyl Alcohol.

Propellants
Aerosol deodorants are designed to work via a thin film sprayed
onto the skin. To create this film, products contain low, medium
and high pressure propellants which produce a spray strong
enough to reach the skin, but not too forceful. In the ingredients
listing these propellants are called Butane, Isobutane and Propane.

Here are some deodorant related videos for you to watch! haha =]

chemical reactions 7/01/2009 08:57:00 PM