Hair Styling

Permanent Waves

These products are designed to permanently change the shape of hair. People with straight hair often use permanent waves to get a little curl in their hair. A permanent wave formula has a reducing agent like thioglycolic acid that reacts with the di-sulfur bonds in the cystine amino acids breaking down the hair structure. Hair is first shaped into curlers, then the product is put on hair. It begins reducing hair and is rinsed with water to stop the reaction. A neutralizing chemical like hydrogen peroxide, is added which reforms the di-sulfur bonds into the new configuration. Perms which intentionally curls hair, chemically increases the number of disulfide bonds by using an oxidizer to uncap the naturally caped sulfides in straight hair. As the name implies, these perms will stay "forever" curly. So, one chemical (a reducer) can make your hair straight, while another chemical (an oxidizer) can make your hair curly. An oxidizing agent, usually a dilute solution of hydrogen peroxide, (also called the neutralizer) is added to reform the disulfide bonds in their new positions. The permanent will hold these new disulfide bond positions until the hair grows out, since new hair growth is of course not treated.


SCOLAR ABSTRACT:
http://www.sciencedirect.com/science/article/pii/S0190962288701516

Hair Relaxers

These products do the opposite of permanent waves. They make curly hair permanently straight. The method is similar you chemically break down hair, reshape it, then reform the protein bonds in the new configuration. Hair is curly is because the keratin proteins contain amino acids called cysteines. These cysteines link to each other by disulfide bonds cap them so that they cannot c(two sulfur atoms connected to each other).The more disulfide bonds, the curlier the hair. Relaxers simply break these disulfide bonds and hemically reform. Classically, hair relaxers use a reducer or a base (the opposite of an acid) such as lye (sodium hydroxide) to break and cap these bonds, thus the neutralizing step stops the reaction. Sometimes ammonium thioglycolate is used but most often it is sodium hydroxide or lithium hydroxide. Unfortunately, sodium hydroxide can burn your skin and damage your hair. The gentler and safer commercial relaxers are still based on the same chemical reactions of breaking disulfide bonds and capping them. Disulfide bonds are not affected by water so when you break the bonds and cap them (in the case of relaxers) they will not go back to their original state.

This is the most damaging chemical treatment for hair!!

SCHOLAR ABSTRACT: refer to page 2
http://www.google.com.my/patents?hl=en&lr=&vid=USPAT4530830&id=3Po9AAAAEBAJ&oi=fnd&dq=hair+relaxers&printsec=abstract#v=onepage&q=hair%20relaxers&f=false

Perms and relaxings both eventually go away, not because the bonds reform, but because your original hair simply grows in, replacing your straightened or curled hair with what you had originally. These chemicals, however, have a tendency to damage your hair, until eventually your hair starts to thin and break, so too much styling can be bad for your hair's health.