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

342 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS A photometer-microscope with a computer-con- trolled fast scanning table is described. With a spe- cial software program, cross-sections of dyed human hair can be analyzed automatically with respect to dye distribution from the outside to the inside of the hair shaft. Very important for such a measure- ment is the producing of microtome cross-sections of defined thickness in a reproducible manner. With some direct dyestuffs the influence of dyeing time on the dye-distribution profile across the hair section is demonstrated. The advantage of carrying out these measurements at a specific wave length at which the dyestuff has its maximum absorption, is shown. SCIENTIFIC SESSION IV HAIR TREATMENTS, PART II Relative detergency evaluation of shampoo for- mulations Donald Thompson, Carole LeMaster, Rebecca Allen, Milton Palmer, and James Whittam, Shaklee Corporation, Research & Development, 1992 Al- pine Way, Hayward, CA 94545 When developing new shampoos, formulators need an easy way by which to assess the relative deter- gency of the prototype to a control shampoo. To address this problem, we have developed a rapid and precise procedure for hair-swatch soiling and treatment. Sebum residues are determined after treatment using gas chromatography and computer- aided data reduction. The new treatment technique was found to be significantly more precise than the "traditional" finger-squeeze procedure. This pro- cedure was used to evaluate several shampoo for- mulations and to investigate component removal and total sebum residue after treatment. Differences in relative detergency were evaluated at two sebum soiling levels using a nine-component sebum in hexane solution. After shampoo treat- ment, the analysis of the residual sebum present indicated that some sebum components were re- moved less extensively than others. This observation led to the investigation of the possible concentration of various sebum components with repeated soiling and washing with the same shampoo formulation. The development and validation of the technique will be described along with plans for future inves- tigations. Foam stability fundamentals James A. Wingrave, E. I. dupont de Nemours & Co., 1213 Jackson Laboratory, Deep Water, NJ 08023 Since foam is an unstaNe state of nature, control over its decay rate is the goal of foam stability studies. Hence, the desired control in any foam sta- bility investigation is to either increase or decrease the decay rate. These respective processes are re- ferred to as foam stabilization or foam breaking. In this presentation the physical and chemical fac- tors responsible for stabilizing foam will be exam- ined in both the absence and presence of a foamicide or soil. In the former case, where no soil is present, the relationship of bubble geometry, viscosity, sur- factant diffusion, and vapor and air diffusion to foam and bubble stability will be investigated. Tests to measure these elements of foam stability will be presented. When soil is present, the rate-limiting step in foam stability becomes dependent upon the interaction of the foam and soil. The mechanism by which soil destabilizes foam will be delineated, and some test methods suitable for studying these mechanisms will be examined. Lather--its importance to the consumer and to the formulating chemist J. Roger Hart, Organic Chemicals Division, W. R. Grace & Co., 55 Hayden Ave., Lexington, MA 02173 The ability of shampoos to form a creamy, rich lather, while commonly recognized as being im- portant to the consumer, has often been considered to be of little or no technical importance by the cosmetic chemist. A new look at the foaming and lathering properties of shampoos, with particular emphasis on the cru- cial differences between lather and foam, adds a new dimension to the selection of ingredients and the formulation of successful products. The ability of the lather to aid in distributing the product through the hair, increasing the viscosity to hold the diluted shampoo in place, assists in the suspending of soil, and as an indicator of the completeness of rinsing is an important technical benefit. The achievement of good lather properties has, however, been confused by the use of dilute foam test methods as a measure of the lathering ability of the product. Newer methods have been patterned on more realistic conditions and these test results are shown to compare quite favorably with actual salon evaluations. Examples of misleading results from the traditional dilute test methods and their potential for misinterpretation will be demon- strated. The principal environmental and formulation fac- tors which influence lather volume and quality will also be discussed in light of these new techniques.