Waving and relaxing preparation

1. Waving and relaxing preparation

2. Waving and relaxing preparation • From the time when early Egyptian curled their hair by means of wet mud, and through the Romans up to present day, the desire of all women has been to possess an attractive & beautiful coiffure. • Curly or wavy hair is more attractive than straight hair & at the same time provides more opportunities for rearrangement in a suitable fashionable styles.

3. Basically these processes involve breaking the bonds holding the polypeptides chains of keratin together, and restoring them in a manner which imparts the desired shape to the hair Hydrogen bonds Water Salt Link Strong acids , strong alkali Disulphide Bonds Reducing agents

4. Waving The first P. Waves : Electric heaters + alkaline solution, based on ammonia and / or borax to break salt and peptide, later sodium sulphite was added disulphide bond Disadvantages: 1- rebuilding by atmospheric oxidation 2- High pH 3- long Processing time Major breakthrough came with : Thioglycollic acid, capable of reducing disulphide bonds at moderate pH and reasonable processing times.

5. Reactions involved polypeptide – S – S – polypeptide 2 Polypeptide – SH pH values between 9-9.5 recommended by using ammonium Hydroxide Bad small (Rotten eggs). Sodium Hydroxide Monoethanlamine Ammonia (Upper pH 10) , Not volatile

7. Neutralizing or rebuilding by Oxidation : this involve : 1- Oxidation of excess thioglycolate and the hydro sulfide groups on the hair 2- Reduction of the pH 3- Drying Can be achieved by: 1- atmospheric oxygen 2- more affective with hair dryer 3- most commonly used, hydrogen peroxide lotion.

8. Low pH Waving Lotions 1- increasing concentration 2- temperature or 3- Swelling agent • 19 % solution of ammo. thioglycolate buffered at PH 7 perms • in less than 10 minutes. 2) Ammoium thiogl. at pH = 6 + swelling agent (urea) to accelerate the process 3) Glyceryl monothioglycollate, with heating cap. CH2O . CO. CH2 -SH I CHOH I CH2OH

9. Low PH Waves Hazard Low pH increase lipid solubility Increase percutaneous absorption and toxicity. Additives Cold wave lotions are extremely reactive , additives should be tested on mixing and after storage. 1) their effect on the pH of the solution 2) their effect on the reducing power. 3) the effect of pH and thioglycollate on the additives. 4) the combined effects on the hair, scalp.

10. Wetting agents The ensure contact and to facilities penetrations of the hair shaft. Cationic can be used, but non-ionics (Polysorbate-80) are preferred. Opacifiers To give richness and mildness latex suspensions, or emulsions

11. The effect of waving lotions on the hair Stress elongation Normally the hair breaks at 60% elongation. The stress / strain at the first inflection will never returns to normal. 1- some of the peptide links broken 2- hydrosulphide not finding them sufficiently near. Relaxing - Thioglycollate usually to mild. - Sodium Hydroxide is the most common. In which the C-S bond of cystein rather than S-S which is attacked.