THE CHEMISTRY OF HAIR RELAXING

Transcription

1 Slide 1 Cosmetology II THE CHEMISTRY OF HAIR RELAXING Page1

2 Slide 2 COPYRIGHT Copyright Texas Education Agency, 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. 3) Any portion reproduced must be reproduced in its entirety and remain unedited, unaltered and unchanged in any way. 4) No monetary charge can be made for the reproduced materials or any document containing them; however, a reasonable charge to cover only the cost of reproduction and distribution may be charged. 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 outside the state of Texas MUST obtain written approval from TEA and will be required to enter into a license agreement that may involve the payment of a licensing fee or a royalty. For information contact: Office of Copyrights, Trademarks, License Agreements, and Royalties, Texas Education Agency, 1701 N. Congress Ave., Austin, TX ; phone ; copyrights@tea.state.tx.us. Page2

3 Slide 3 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. Page3

4 Slide 4 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. Page4

5 Slide 5 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 Strand of human hair at 200x magnification Image from Wikimedia Commons, the free media repository 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. Page5

6 Slide 6 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. Page6

7 Slide 7 RELAXERS Thio Relaxers Hydroxide Relaxers Sodium Hydroxide Two most common hair relaxers are thio and sodium hydroxide relaxers. Page7

8 Slide 8 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. Page8

9 Slide 9 HYDROXIDE RELAXERS Active ingredient is hydroxide ion Highly alkaline product ranging usually from a ph of Types include: Sodium Potassium Lithium Guanidine hydroxide Hydroxide relaxers are not compatible with thio relaxers because they use a different chemistry. Page9

10 Slide 10 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 Page10

11 Slide 11 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 Page11

12 Slide 12 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. Page12

13 Slide QUESTIONS? Page13

14 Slide 14 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 Page14