Download PowerPoint - The Chemistry of Hair Relaxing

THE CHEMISTRY OF HAIR
RELAXING
Cosmetology II
COPYRIGHT
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CHEMICAL HAIR RELAXING
A process or service that
rearranges the structure
of curly hair into a
straighter or smoother
form
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CHEMICAL HAIR STRUCTURE
• Hair is made up of:
• Protein – 90%
• Carbon – 51%
• Oxygen – 21%
• Hydrogen – 6%
• Nitrogen – 17%
• Sulfur – 5%
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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:
Strand of human hair at 200x magnification
• Hydrogen bonds
• Salt bonds
• Disulfide bonds
Image from Wikimedia Commons,
the free media repository
Copyright © Texas Education Agency, 2014. All rights reserved.
DISULFIDE BONDS
• Strong, chemical side bond
• Cannot be broken by water
• Can be broken by chemical hair
relaxers
• Alters the shape of the hair
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RELAXERS
Thio Relaxers
Hydroxide Relaxers
Sodium Hydroxide
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
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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
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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
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THE BASICS OF
CHEMISTRY
(click on link)
Image from video
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WARNING
Caution is advised as relaxers
can literally dissolve or melt
the hair
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13
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
Copyright © Texas Education Agency, 2014. All rights reserved.