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Presentation Notes The Chemistry of Hair Relaxing

The Chemistry of Hair Relaxing Copyright © Texas Education Agency, 2014. All rights reserved.

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THE CHEMISTRY OF HAIR RELAXING

Cosmetology II



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COPYRIGHTCopyright © Texas Education Agency, 2014. These Materials are copyrighted © and trademarked ™ as the property of the Texas Education Agency (TEA) and may not be reproduced without the express written permission

of TEA, except under the following conditions:1) Texas public school districts, charter schools, and Education Service Centers may reproduce and use copies

of the Materials and Related Materials for the districts’ and schools’ educational use without obtaining permission from TEA.

2) Residents of the state of Texas may reproduce and use copies of the Materials and Related Materials for individual personal use only, without obtaining written permission of TEA.

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Private entities or persons located in Texas that are not Texas public school districts, Texas Education Service Centers, or Texas charter schools or any entity, whether public or private, educational or non-educational, located

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For information contact: Office of Copyrights, Trademarks, License Agreements, and Royalties, Texas Education Agency, 1701 N. Congress Ave., Austin, TX 78701-1494; phone 512-463-7004; email: [email protected].

Copyright © Texas Education Agency, 2014. All rights reserved.



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CHEMICAL HAIR RELAXING

A process or service that rearranges the structure

of curly hair into a straighter or smoother

form


All relaxers and all permanents change the shape of the hair by breaking disulfide bonds.



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CHEMICAL HAIR STRUCTURE

• Hair is made up of:

• Protein – 90%

• Carbon – 51%

• Oxygen – 21%

• Hydrogen – 6%

• Nitrogen – 17%

• Sulfur – 5%


The elements in hair are also known as: COHNS Elements C – Carbon O – Oxygen H – Hydrogen N – Nitrogen S – Sulfur These elements are also found in skin and nails.



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HAIR ANALYSIS

• Hair proteins are made of amino acids

• The cortex is made up of polypeptide chains

• These chains are cross-linked by side bonds

• Types of side bonds include:• Hydrogen bonds

• Salt bonds

• Disulfide bonds

Image from Wikimedia Commons, the free media repository


Strand of human hair at 200x magnification

Polypeptide chains cross-linked with side bonds together are responsible for the extreme strength and elasticity of human hair. Hydrogen and salt bonds can be broken by heat and moisture. Disulfide bonds are strong and can be broken by chemical hair relaxers that alter the shape of hair.



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DISULFIDE BONDS

• Strong, chemical side bond

• Cannot be broken by water

• Can be broken by chemical hair relaxers

• Alters the shape of the hair


Hair relaxers straighten the hair by breaking disulfide bonds and the neutralizer hardens the hair in its straight form.



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RELAXERSThio Relaxers

Hydroxide Relaxers

Sodium Hydroxide

Two most common hair relaxers are thio and sodium hydroxide relaxers.



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THIO RELAXERS

• pH factor of 10 and higher

• Thicker which helps hold hair in a straight position

• Hair softens and swells during the relaxer process and disulfide bonds are broken

• A neutralizer is used to rebuild disulfide bonds


The neutralizer provides an oxidation reaction that rebuilds the hair bonds in a straightened form. It breaks bonds by adding hydrogen atoms to the two sulfur bonds within the disulfide bond. Hydrogen peroxide is usually used.



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HYDROXIDE RELAXERS

• Active ingredient is hydroxide ion

• Highly alkaline product ranging usually from a pH of 12-14

• Types include:

• Sodium

• Potassium

• Lithium

• Guanidine hydroxide


Hydroxide relaxers are not compatible with thio relaxers because they use a different chemistry.



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SODIUM HYDROXIDE(NaOH)

• Commonly called lye relaxers

• Most common type of hair relaxer

• Highly caustic

• pH is often over 13.5 which is highly corrosive


Sodium Hydroxide is the same chemical used in drain cleaners and chemical hair depilatories



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THE BASICS OF CHEMISTRY

(click on link)


Image from video

Click on hyperlink to view video: Basics of Chemistry Clip from the Milady Standard Cosmetology 2012 DVD Series http://youtu.be/N0PVlegJv8Y



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WARNING

Caution is advised as relaxers can literally dissolve or melt

the hair


Be sure to wear gloves and protective clothing when mixing chemicals. Always follow manufacturer’s processing directions.



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QUESTIONS?

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REFERENCES AND RESOURCES

Images:

• Microsoft Office Clip Art: Used with permission from Microsoft.

• Wikimedia Commons, the free media repository

Textbook(s):

• Halal, J. (2009). Hair structure and chemistry simplified: Exam review/John Halal. Clifton

Park, NY: Milady/Cengage Learning.

• Milady standard cosmetology: Situational problems. (2012). Clifton Park, NY: Cengage Learning.

YouTube™:

• Basics of Chemistry

Clip from the Milady Standard Cosmetology 2012 DVD Series

http://youtu.be/N0PVlegJv8Y


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