340 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The build-up of static charges on hair (phenomenon of fly-away) has been the subject of intermittent investigations. A directional triboelectric effect and a strong dependence on the humidity of the sur- rounding atmosphere were reported to be the main features of this process. Since triboelectrification is a surface phenomenon, it is sensitive to the chemical structure of the hair surface. The introduction of foreign species on the surface can strongly affect both the magnitude and the direction of electron transfer. The present communication describes the use of var- ious polymers and metals as contact probes to study the effect of surface modification on the triboelectric behavior of human hair. Measurements of both the sign and density of generated charges were con- ducted. The fibers were modified in various ways, including the adsorption of cationic polyelectro- lytes, monomeric or polymeric long alkyl chain quaternary ammonium salts, and the formation of polymer or polymer-detergent complexes on the surface. The primary effect of all these treatments is to alter the electrochemical potential of the fiber surface, and the occasional accompanying increase in electrical conductivity at 25-30% relative hu- midity appears to be of trivial importance. It was concluded that suppression of the static charge gen- eration can be achieved by reducing the difference in work functions between the contact probe used and the hair keratin. This can be done by the proper choice of comb material or the surface modification of the fiber. Factors affecting the kinetics of disulfide bond reduction in hair R. Randall Wickerr, Ph.D., and Bruce G. Barman, Ph.D., Procter & Gamble Company, Miami Valley Labs., P.O. Box 39175, Cincinnati, OH 45247 The kinetics of hair disulfide bond reduction by dihydrolipoic acid (DHL), dithiothreitol (DTT) and 1,3-dithiopropanol (DTP) and their analogues have been investigated using a single fiber technique. Structure activity relationships are described. It is shown that the overall rate of reduction may be altered by factors that affect the equilibrium con- stant of the reaction between the reducing agent and hair or the rate of diffusion of the reducing agent into the hair. Monothiol analogues of DHL are many times slower in reducing hair than is DHL which correlates with the much higher equilibrium constant of the reac- tion between DHL and hair disulfides. Reduction with DHL leads to the formation of a moving boundary of reducing agent in the hair. This boundary is clearly visualized by histochemical mi- croscopic techniques. Structure activity relationships in analogues of DTT and DTP illustrate the effects of hydroxyl groups on reactivity and differences between the formation of five-membered dithiolane or six-membered di- thiane rings on oxidation. SCIENTIFIC SESSION II HAIR PROPERTIES, PART II Connection between damage and electrostatic charge of hair fibers Peter Busch, Ph.D., Henkel KGaA,4 Dusseldorf, West Germany The generation of electrostatic charge by combing (or brushing) hair fibers not only leads to hair care problems ("fly-away phenomenon"), but also to marked hair damage. Owing to the opposite elec- trostatic charges, the hair fibers adhere to the sur- faces of combs or bristles of brushes and get stretched. The consequences of this stretching are: The hairs entangle, which causes high combing forces, and the hair surfaces get abraded, which leads to unfa- vorable hair-splitting values. The stress-strain be- havior of the electrostatically charged hairs, how- ever, is scarcely affected. "Self dynamic phenomena" play an important role in damaging the hair surface. The electrostatic influence was proven by specially developed measuring devices. Some particulars of the abrasion process are shown in cinematographic studies. The efficacy of several products will be ex- plained. Distribution of sulfur and crosslinking in hair Emory Menefee, 53 !3 Rosalind Ave., Richmond, CA 94805 The varying sulfur contents of mammalian keratins, including human hair, are not accounted for by as- suming that they have more or less of a matrix protein with uniform cystine/cysteine content. Rec- ognition in recent years of the presence of an "ultra- high sulfur" fraction suggests that perhaps a linear combination of three components may account for most of the variation. This is borne out by calcu- lation of the composition of a normal human hair and a trichothiodystophic human hair from fraction compositions taken from wool analyses. It is still speculative at present whether such fractions rep- resent components in situ or are somewhat artifac- rive. Furthermore, even for fibers with similar sulfur content, differences in crosslinking distri- bution among intra- and inter-molecular crosslinks can profoundly affect physical properties.

ABSTRACTS 341 Behavior of hair fibers in torsion Linda Albrecht and Leszek J. Wolfram, Ph.D., Clairol Research Labs., 2 Blachley Rd., Stamford, CT 06922 The unique tensile properties of keratin fibers in water led Speakman to develop the technique of fiber calibration which has become one of the main- stays of hair testing methodology. The obvious ad- vantage of using the calibrated fibers as their own controls is frequently overshadowed by the necessity of using water as the calibration medium. We have found that the torsional properties of hair--unlike the tensile ones--are not subject to such limitation and thus offer themselves as a convenient mode for fiber calibration at any desired level of humidity. The calibration technique, together with the evi- dence supporting i.ts reliability, is fully described and its utility as a sensitive fiber-testing tool is demonstrated on fibers with varied histories of treatments. FTIR spectroscopy of hair oxidation John Strassburger and Miklos M. Breuer, Ph.D., The Gillette Co., 1413 Research Blvd., Rockville, MD 20850 Oxidative hair damage was measured using a high pressure diamond anvil cell with a Fourier transform infrared spectrometer. Disulfide bond cleavage by bleaching or waving was spectroscopically distin- guished from Bunte salt hair modification. Oxida- rive damage was quantified by normalizing the S-O band intensity (near 1040 cm-•) against various keratin band intensities. The band ratio pro- ducing the most precise quantitative results for rep- licate determinations was established. Band intens- ities obtained after spectral subtraction produced the most precise results. The degree of oxidative damage was measured for different chemically pro- cessed blond and brown hair and hair exposed to environmental factors as well as combinations thereof. These included sunlight, heat, moisture, artificial weathering, waving, and bleaching. The variability, between hair tresses, or replicate cos- metic treatments was assessed, as well as the mea- surement variability within a given tress. These two variabilities were found to be similar. Single bleached hair fibers were also analyzed along their length for degree of oxidation. The oxidation level was found to increase from the root to the tip. SCIENTIFIC SESSION III HAIR TREATMENTS, PART I Oxidative dyeing of keratin fibers Keith C. Brown, Ph.D., David Cohen, and Stanley Pohl, Ph.D., Clairol Inc., 2 Blachley Rd., Stam- ford, CT 06922 Dye uptake by hair and other keratinic fibers has been measured by a reflectance technique. Using a statistical experimental design, color formation from a single pair of reactants and hydrogen per- oxide has been used to define and quantify many of the factors that control the process. Although dyeing time (10-30 minutes) and peroxide concen- tration (2-10%) have little effect, color intensity depends strongly on reactant concentration and added surfactants. These results can generally be predicted from the solution kinetics of the coupling reaction where the rate-controlling step is formation of a reactive in- termediate from hydrogen peroxide followed by a series of faster oxidative and coupling steps to give the dye. Thus, it appears that the chemistry involved in ac- tual hair dyeing practice closely parallels that ob- served in solution. Diffusion of semipermanent dyestuffs in human hair S. K. Han, Ph.D., Y. K. Kamath, Ph.D., and H. D. Weigmann, Ph.D., Textile Research Insti- tute, P.O. Box 625, Princeton, NJ 08542 Diffusion of semipermanent hair dyes into human hair fibers was investigated. The effects of pH, con- centration, and temperature, as well as solvent com- position of the dyebath on the rate of diffusion, were studied. The apparent diffusion coefficient, D, and the activation energy of diffusion, ED, were deter- mined using both an extraction method and mi- crospectrophotometry. Thermodynamic equilib- rium parameters between the dyebath and the hair fiber such as dye partition coefficient, K, and dye affinity, -z5 •o, were also determined. It was found that the diffusion coefficients are gen- erally independent of concentration but depend on the pH of the dyebath. The solvent composition of the dyebath plays a critical role in the thermody- namic equilibrium parameters so that the value of the partition coefficient, K, increases by almost an order of magnitude from aqueous ethanol solution (50% vol) to pure aqueous solution for the dyes studied in this paper. Determination of the dye-distribution in human hair cross-sections using a scanning photometer microscope G. Blankenburg, H. Philippen, P. Baurschmidt, and V. Bollert, Deutsches Wollforschungs Institut, an der Rheinisch-West falischen, Technischen Hochschule Aachen, West Germany