1. Soc. Cosmet. Chem., 25, 407-421 (August 1974) Polymerization into Human Hair CLARENCE ROBBINS, Ph.D.,* RICHARD CRAWFORD, Ph.D.,* D. W. McNEIL, B.S.* JULIUS NACHTIGAL, Ph.D.,* and GIUSEPPI ANZUINO, Ph.D. '• Synopsis-THIOGLYCOLIC ACID (TGA)-CUMENE HYDROPEROXIDE (CHP) and BISULFITE--CHP systems are described for po]ymerizing METHYL METHACRYLATE (MMA) in HUMAN HAIR. An ethanol-water solvent system was employed. Diffusion rate control appears to predominate over a variety of reaction conditions. The influence of reagent concentrations and so]vent effects on the reaction is also describe:]. POLY- MERIZATION is shown to occur more rapidly into either reduced-oxidized or bleached hair than into chemically unaltered hair. Partial hydrolysis of the hair fibers containing polymethyl methacrylate (PMMA) provides filament-like fragments, consisting primarily of PMMA, which were examined microscopically. INTRODUCTION Two manuscripts (1, 2) from our laboratories describing chemical reac- tions of human hair containing synthetic polymer have already been pub- lished. This paper describes the polymerization reaction used in our earlier work and some characteristics of the synthetic polymer isolated by hydrolyric methods. Additional references and background to vinyl polymerizations in keratin fibers may be found in the first two articles of this series. EXPERI1VIENTAL Materials Human Hair The keratin fibers used in this investigation were brown human hair,$ from European Caucasians, which were washed with 2% sodium lauryl sul- fate and rinsed thoroughly with deionized water. *Colgate-Palmolive Research Center, 909 River Road, Piscataway, N.J. 08854. This work was conducted at the Colgate-Palmolive Research Center where all correspondence should be addressed. ?Chatilion S.P.A., Largo Chatilion, Verce]li, Italy. Purchased froin De Meo Brothers, New York, N.Y. 4O7

408 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Bleached Hair Detergent-washed European brown hair (10 g) was weighed into a 1-1. beaker and treated with a solution containing 60 ml of 30% hydrogen peroxide and 240 ml of aleionized water, and adiusted to pH 10.2 with con- centrated ammonium hydroxide. After 30 rain the solution was decanted and Reduced-Oxidized Hair the h.qir was thoroughly rinsed with deionized water. Detergent-washed European brown hair was reduced for 30 min with 6% ammonium thioglycolate at pH 9.2 using a 33:1 solution-to-hair ratio followed by oxidation for 5 min with 1.4% sodium perborate using a 40:1 solution-to- hair ratio. Methyl Methacrylate* Monomer was washed with dilute alkali and distilled prior to use. All other chemicals were of reagent grade or of the highest purity available. Procedures Polymerization with TGA-Cumene Hydroperoxide The hair was immersed in 6% ammonium thioglycolate at pH 9.2 for 10 (unless otherwise specified) using a 20:1 solution-to-hair ratio at room tem- perature. The solution was then decanted and the fibers were rinsed for 2 rain with deionized water and immersed at room temperature in water-alcohol (60:40) mixtures of MMA (10%) and CHP (3%) using a 20:1 solution-to- hair ratio (unless other concentrations are specified). After 30 min reaction time, the solution was decanted and the hair was rinsed with water and dried. The amount of add-on was estimated by weight pickup measured at 55% RH before and after reaction. Polymerization with BisullSte-Cumene Hydroperoxide The fibers were immersed in 5% sodium bisulfite dissolved in 45% ethanol for 10 min using a 20:1 solution-to-hair ratio at room temperature. The solu- tion was then decanted and the fibers were rinsed for 2 nfin with deionized water and immersed in a solution of MMA and CHP as described in the above section. Isolation o[ Polymer by Acid Hydrolysis Polymer (PMAA)-containing hair was refiuxed for 11/2hours in 5N hydro- chloric acid using a 50:1 solution-to-hair ratio. The solution was decanted and the fibrous solid was washed with deionized water, filtered, and washed sev- *Borden Chemical Co., Philadelphia, Pa.