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Chemistry for Cosmetics

Chemistry for Cosmetics. Dr Lida Schoen Amsterdam. Human skin. ‘Dirt’ on the skin. water soluble (sweat); oil soluble (sebum, grease); non soluble (sand, skin flakes). Rubbing with water and soap can remove all three. Cleaning the skin: water and soap. Washing dirt from textiles.

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Chemistry for Cosmetics

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  1. ChemistryforCosmetics Dr Lida Schoen Amsterdam

  2. Human skin Chemistry of hair and skin products

  3. ‘Dirt’ on the skin • water soluble (sweat); • oil soluble (sebum, grease); • non soluble (sand, skin flakes). Rubbing with water and soap can remove all three. Chemistry of hair and skin products

  4. Cleaning the skin: water and soap Chemistry of hair and skin products

  5. Washing dirt from textiles with water and soap Chemistry of hair and skin products

  6. ‘Cosmetic’ cleaners Showergel (=shampoo) Chemistry of hair and skin products

  7. ‘Cosmetic’ emulsion • Water • Oil • Emulsifier • Additions • Perfume • Colour Chemistry of hair and skin products

  8. Emulsion: micro Chemistry of hair and skin products

  9. Emulsion: macro Chemistry of hair and skin products

  10. Cream • 2-3% emulsifier + thickener (for stabilisation) • 10% oil like • mineral like paraffin (cheap, doesn’t deteriorate) • vegetable like avocado (what’s good to eat …), • animal like mink (snob appeal) • Water • Perfume • Additive, like • dihydroxyacetone (artificial tanning) • herbals Chemistry of hair and skin products

  11. Flowers, herbals Chemistry of hair and skin products

  12. Hair under microscope Chemistry of hair and skin products

  13. Chemistry: keratin • Hydrogen bridges • Ion-ion (salt) bonds • Disulfide (sulpher) bonds Chemistry of hair and skin products

  14. Keratin (2) Chemistry of hair and skin products

  15. Keratin (3) pH = 5,5 Chemistry of hair and skin products

  16. Keratin (4) cystin Chemistry of hair and skin products

  17. All bonds (schematic) Chemistry of hair and skin products

  18. Chemistry of hair and skin products

  19. Melanin in cortex Eumelanin • black-brown; • large molecules; • easy to light up. Pheomelanin • yellow-red; • smaller molecules; • difficult to light up. Chemistry of hair and skin products

  20. Chemistry of hair and skin products

  21. Hair colour Chemistry of hair and skin products

  22. Hair cleaning: shampoo Detergent: sodium lauryl (=C12) ether sulphate: • cheap • skin friendly • good foam • easy to thicken (with NaCl) Chemistry of hair and skin products

  23. Ether sulfates • Vegetable oil, after hydrolysation and reduction, ethoxylation with ethylene oxide • Alkyl alcohol esterified with sulphuric acid: CH3-(CH2)10-CH2(OCH2CH2)n)OSO3- Na+ with 1<n<4 Chemistry of hair and skin products

  24. Thickener: electrolyte • detergent in water: micelles • NaCl (3-4%) Chemistry of hair and skin products

  25. Conditioner in the past: egg yolk Egg shampoo: • Egg yolk: lecithin Conditioner today: man made • quat = quaternary ammonium compound • silicone Chemistry of hair and skin products

  26. Hair in form1775 today Chemistry of hair and skin products

  27. Hair gel at school Carbomer (brand name in Europe): neutralised cross linked polymer of acrylic (propene)acid CH2=CH-COO-Na+ Chemistry of hair and skin products

  28. Bleaching (1) • Decomposition of melanin by oxidation in alkaline (ammonia) environment; • carboxylated derivatives soluble at higher pH’s. Chemistry of hair and skin products

  29. Bleaching (2) • Bleaching powder: persulphate:(O3S-O-O-SO3)2- 2 Na2S2O8 -> 2 Na2S2O7 + O2 • Hydrogen peroxide,(max. 12%, pH = 4), optimum melanin bleaching at pH  pKa (11,5) of the peroxide-anion. • In practice: pH = 10. H2O2(aq) 12% not stable at pH = 10. Chemistry of hair and skin products

  30. Types of hair colouring • permanent • semi-permanent • temporarily • Oxidative • Direct Chemistry of hair and skin products

  31. Hair colouringproducts • Natural • Metal • Permanent (synthetic dyes) • Semi-permanent (natural en synthetic dyes) • Temporarily (synthetic dyes) Chemistry of hair and skin products

  32. Chemistry of hair and skin products

  33. Chemistry of hair and skin products

  34. walnut henna Chemistry of hair and skin products

  35. Semi-permanent hair colouring • in and under cuticle • 4-6 washings • till 30% grey covering Chemistry of hair and skin products

  36. Metal ‘dyes’ • Acetates or sulphates of: lead, silver, iron, copper, cobalt, bismuth, manganese, zinc • Sulphide bonds with sulphur from keratin • Toxic properties! • Sensitive to oxidation Chemistry of hair and skin products

  37. Permanent hair colouring • Oxidative dyes: ‘development’ with hydrogen peroxide • Not washable • Till 100% grey covering Chemistry of hair and skin products

  38. Developers and couplers = developers = couplers Chemistry of hair and skin products

  39. Examples of couplings Chemistry of hair and skin products

  40. Summary chemical ‘trick’ • Mix two (or more) kinds of small molecules; • cover hair with mixture; • small molecules intrude the hair cortex (higher pH will help to open cuticula); • inside the cortex small molecules react to much bigger molecules; • The big molecules are captured in the cortex, they can’t leave: permanent hair dye Chemistry of hair and skin products

  41. Bath salts • Salt • kitchen salt: NaCl (cheap, crystals) • soda : Na2CO3 (softener) • bicarbonate: NaHCO3 (solubility) • phosphate: Na3PO4 (complexer) • Perfume • Colour(water soluble food colour) • Extra(chamomile, herbals) Chemistry of hair and skin products

  42. Perfume (1) • Natural (past) and synthetic (aldehydes, ketones, esters) • Mixture of 3 groups ‘notes’: • Top; • Middle; • Base. Chemistry of hair and skin products

  43. TOP lime, lemon , mandarin, orange, grass, apple, pineapple, cassis, raspberry, peach citrus green fruity MIDDLE jasmin, rose, violet, muguet floral sandalwood, cedarwood, ambery, musky, vanilla, sweet hay BASE woody powdery Chemistry of hair and skin products

  44. ‘Our’ Chanel Allure • citrus: 15 drops (top) • lily of the valley: 8 drops (top/ middle) • rose: 2 drops (middle) • jasmin: 10 drops (middle) • floral bouquet: 5 drops (middle) • sensual: 10 drops (base) Chemistry of hair and skin products

  45. Dilution • With min 70% alcohol • Denaturated (tax reasons) with bergamot (citrus) or DEP (di-ethylphtalate) • Perfume: 20% oils • Eau de Toilette: 5% oils Chemistry of hair and skin products

  46. Allure – Fragrance Description From the Chanel website: • The concept of Allure was Coco Chanel’s ideal: an innocent seduction without artifice, an unforgettable elegance transcending words and conventions. • Fragrance family: floral, fresh, oriental. A faceted fragrance that mixes notes of the Orient with abstract flowers. • A simple jewel that combines 6 complex facets. In Allure, you’ll find bergamot, mandarin, water lily & magnolia, jasmine and may roses, vetiver and finally, the velvety sensuality of vanilla. Chemistry of hair and skin products

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