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chemistry of hair

chemistry of hair

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  • Dimethicone
  • Transcript

    • 1. Chemistry of Hair
      By: Marlene Simas, Tavis Cano, and Kathleen Good
    • 2. Hair Structure
      Made up of 3 layers
      Outer covering
      Body temperature regulation
    • 3. Hair Composition
      88% is made up of proteins
      Mainly Keratin
      Many polypeptide chains
      Broken down = individual amino acids
      Right combo = specific protein
      Natural Hair pH is 5
    • 4. A Helix Coil
      1 hair = 3 “alpha helices”  protofibril
      9 protofibrils bundled in a cirle  11 stranded cable microfibril
      100s of microfibrils in a bundle  macrofibril
      Cortex of hair fiber
    • 5. Natural Hair
    • 6. Keratin
      Alpha helix polypeptide chain in human hair
      3.6 amino acids per turn in the helix
      Peptide bond
      Between the Carbon and Nitrogen
    • 7. Bonding in Keratin Protein
    • 8. Bonding
      Hydrogen bond: Is between the coils of the alpha helix
      Can change the shape of hair
      Salt bond: An ionic bond between side chain of the basic to the side chain of an acidic amino acid
      Happens parallel to the hair
      Strength and elasticity
    • 9. Bonding cont.
      Cystine Bond: Formed by the crosslinks between cystine residues (amino acids) of the main polypeptide chains
      perpendicular to the hair & between polypedptide chains
      1 Cystine bond every 4 turns of the alpha helix
      Sugar Bond: Is between side chain of an amino
      acid with OH group and acid amino group
      Perpendicular to the hair
      Toughness and some strength
    • 10. How Shampoo Works
    • 11. Shampoo
      Essential cleaning substances
      Determines cleansing and lathering characteristics
      cleansing, foam, condition, viscosity and aesthetic appeal combined with safety and mildness in use.
    • 12. Surfactants
      Are divided based on the hydrophilic head
      Anionic: negative charge
      Cationic: positive charge
      Amphototeric – positive and negative charge
      Nonionic – no charge
    • 13. Sodium Lareth Sulfate
    • 14. Conditioners
      Are cationic
      Do not rinse out completely
      Leave hair coated with thin film
      Hydrophobic head is what gives hair conditioning ability; smoothing the hair and giving it weight
      6 categories:
      Thermal Protection
    • 15. Hexadecyltrimethylammoniumchloride
      Are usually quaternary ammonium compounds
      4 R groups to 1 N
      Can also be tertiary
      Form the thin coating on the hair shafts
    • 16. CG Method! 
      Lorraine Massey
      All products used – conditions, gels, creams, sprays, etc – are all free of
      Silicones: -cone, -conel, -xane
      Can have any hair type to try
    • 17.
    • 18. Wet hair stretches as the temporary hydrogen bonds are broken
      When blow dried will return to the alpha keratin shape
    • 19. Brazilian Blow Out
    • 20.
    • 21. What’s In It?
      Methylene Glycol
    • 22. Formaldehyde; What is it?
      Organic compound CH2O
      Simplest Aldehyde
      IUPAC name: Methanal
      Systematic name: Formaldehyde
      Colorless gas with a pungent odor
      Important in polymers
      Used as disinfectants
      Used for preservation of biological specimens
      Widespread use: toxicity, volatility, carcinogenic
      Other names: Formal, Methlyaldehyde, Methylenegylcol, Methylene Oxide
    • 23. Formaldehyde
      Russian chemist AleksandrButlerov & August Wilhelm von Hofmann
      Produced by catalytic oxidation of methanol
      Most common catalysts: Silver, iron,
      2 CH3OH + O2 -> 2 CH2O + 2 H2O
      CH3OH -> H2CO + H2 (dehydrogenation)
    • 24. Cont.
      Building block
      Highly reactive
      Tissue fixative
      “My eyes were irritated for a week or so after the treatment & my hair burned my boyfriends nose...”
    • 25. Properties Of Formaldehyde
      Molecular formula: CH2O
      Molar mass: 30.03 g mol−1
      Exact mass: 30.010564686 g mol-1
      Appearance Colorless gas
      Density: 1.38 g cm-3
      Melting point: -92 °C, 181 K, -134 °F
      Boiling point: -21 °C, 252 K, -6 °F
      Solubility: in water 400 g dm-3
      log P: 0.350
      Acidity: (pKa) 13.3
      Basicity: (pKb) 0.7
      Dipole moment: 2.33 D Structure
      Molecular shape: Trigonal planar
    • 26. Health Effects of Formaldehyde
      Runny nose
      Sore throat
      Sleeping difficulties
      Breathing difficulties
      Sinus irritation; nose bleed
      Chest pain
      Decreased lung capacity
      Abdominal pain
      Respiratory problems (pneumonia)
      Low Level Exposure
      Acute Exposure
    • 27.
    • 28. Methylene Glycol
      Also known as Formaldehyde monohydrate or methylene glycol
      Chemical formula: CH4O2, or H2C(OH)2
    • 29. Cont.
      Is a product of the hydration of formaldehyde
      Predominates in water solution
      Methanediol is listed as one of the main ingredients of the Brazilian Blowout, even though the California-based manufacturer claims that the product contains no formaldehyde
    • 30. Glutaraldehyde…What is it?
      Pungent & oily liquid at room temperature
      IUPAC name: Pentene-1,5-dial
      Other names: Pentanedial, Glutardialdehyde, Glutaricdialdehyde
      Used to disinfect medical and dental equipment
      Organic compound
      Formula: CH2(CH2CHO)2
    • 31. Cont.
      Produced by oxidation of cyclopentene
      Used in biological electron microscopy as fixative
    • 32. Health Effects
      Sever eye, nose, throat and lung irritation
      Main source of occupational asthma
    • 33. Perm
    • 34. Ammonium thioglycolate
      A solution containing ammonium thioglycolate contains a lot of free ammonia, which swells hair
      In the perm solution reduces the disulfide cystine bonds in the hair.
      It removes crosslinks. After washing, the hair is treated with a mild solution of hydrogen peroxide, which oxidizes the cysteines back to cystine.
      New bonds instruct the structural rigidity necessary for a successful perm. The rigidification process is akin to the vulcanization of rubber, where commonly polysulfide linkages are used to crosslink the polymer chains.
      Not all disulfides are reformed
      Result: the hair is weaker than before the permanent was applied and repeated applications over the same spot may eventually cause strand breakage
    • 35. Permanent Hair Wave
      Disulfide bond formation can produce curls in hair by the permanent wave process
      Hair keratine=many protein alpha helices
      3 alpha-helices interwoven in coil=protofibril
      11 protofibrils bonded and coiled together=microfibril
      Hundreds of microfilbrils cemented into buncle=macrofibril
    • 36. Disuldife Bonds in Hair
      Formed by oxidation of sulfhydrl groups on cysteine
      Different protein chains loop within a single chain & help by strong covalent disulfide bonds
    • 37. Reducing Agent
      Perming requires a basic reducing substance: Ammonium Thioglycolate
      Added to reduce/rupture some disulfide cross-links
    • 38. The Results
      Since the alpha-helices are ruptured and no longer tightly cross-linked, the alpha helices can shift positions
      Rollers or curlers or inserted
      Oxidizing agent is added to reform bonds into new positions
    • 39.
    • 40. Structure of Hair 
      • Outer layer of hair shaft is called the cuticle
      • 41. consists of many microscopic scales
      • 42. when they are aligned they give the appearance of shiny hair
    • Hair Color 
      • Natural color of hair depends on 
      • 43. The ratio and quantities of 
      • 44. Eumalinen and Phaeomelanine
      • 45. These two make up only 1% of hair structure
      • 46. Phaeomelanine is resposible for red to blonde colors 
      • 47. Eumalinen make brown to black shades of hair
      • 48. While you can have one or both, the absence of both results in white/grey hair
    • Bleaching
      • Bleaching is a process used to strip color from hair and can be done for three reason
      • 49. Highlighting is a cosmetic effect of lightening streaks or sections of hair
      • 50. Blonding is a process that strips away original color and adds color to hair to achieve blonde appearance
      • 51. Usually achieved by a mixture of bleach and a coloring agent 
      • 52. Precoloring makes hair a blank canvas which makes hair color applied after words brighter
    • Bleaching
      • Cosmetic bleaches use the oxidizing effects of hydrogen peroxide
      • 53. A low volume of peroxide (5-30%) in a cream form combined with powder bleach creates a blue paste
      • 54. this is applied and left until desired amount of color is stripped from hair then rinsed out
      • 55. usually has a pH of 8 or 9
    • Bleaching
      • For bleach to change the color of hair it has to be able to penetrate below the cuticle surface
      • 56. Usually done by mixing bleach component with a alkaline solution (often ammonia)
      • 57. This alkali swells the hair fiber causing cuticles to separate and open, allowing bleach to penetrate the cortex 
    • Bleaching   
      • Bleach reacts more readily with dark eumelanin pigments than with phaeomelanin pigments
      • 58. If hair has been previously colored with permanent dye bleaching could vary in effectiveness 
    • Bleaching
      • Bleaching is very damaging to hair as well as emitting a sulfuric odor
      • 59. Hydrogen peroxide breaks the sulfur bonds which releases larger amounts of sulfur
      • 60. This causes hardening, loss of mass, and produces smell
      • 61. minimized by using low levels of peroxide in cosmetic bleach
      • 62. If using metal implements to apply bleach they can oxidize, the reaction following this with bleach can turn hair green
    • 63. Hair Dye
      • Three types of hair dye
      • 64. Temporary - lasts 1-3 washes and involves no chemical reactions with the hair 
      • 65. Pigments are applied to surface without penetrating further
      • 66. Semi-permanent - stays in 5-15 washes usually made from vegetable dyes, mainly designed to adhere tightly to cuticle surface
      • 67. no chemical reactions take place
    • Hair Dye
      • Types of hair dye cont.
      • 68. Permanent  - lasts indefinitely until hair grows out or chemically treated to remove color 
      • 69. First safe permanent hair dye created in 1907 by Eugene Schueller
      • 70. Main ingredient was paraphenylenediamine
      • 71. Often combines bleaching and coloring agent
      • 72. Dye molecules enter the hair cortex where they react and become trapped as the cuticles close
      • 73. A post coloring conditioner is used to encourage cuticles to close and realign to make color last longer
      • Basic Orange 31
      • 74. 2-[(4-aminophenyI)azo] -1,3- dimethyl - 1H-               Imidazolium Chloride
      • 75. C11H14N5Cl
      • 76. Basic Brown 16
      • 77. 8-[(4-Amino - 1 Phenyl)azo] -7 - hydroxy N,N,N Trimethyl - 2 - Naphthalenaminium Chloride
      • 78. C19 H21N4 OC1
    • Hair Dye
      • Mechanism of permanent hair dye involves three steps
      Oxidation of 1,4 - diaminobenzene derivative to the quinone state
      Reaction of this Diimine with a coupler 
      Oxidation of the resulting compound to gives the final dye
    • 79. Hair Dye
      • Adverse effects include
      • 80. Temporary skin irritation and allergies
      • 81. Hair breakage
      • 82. Skin discoloration
      • 83. And unexpected hair color results