2005 ANNUAL SCIENTIFIC SEMINAR Results and Discussion Initial panel tests using dispersion application of the hair condition found a 66% preference for the hair conditioner with the polymer against a national brand. A repeat study found a 64% preference of the formulation containing the polymer over the formulation without. XPS analysis found higher silicone levels on the hair tresses exposed to the dispersed conditioner formulation with the polymer compared to the formula without polymer. This data is consistent with the results of the panel test preference study. The formulation containing the polymer does not show any quaternary nitrogen or characteristic hair fiber sulfur/nitrogen signals, indicating a uniform silicone over layer coverage of greater than 7 run on the hair fiber. The formulation without the polymer shows both the quaternary nitrogen and characteristic hair fiber sulfur/nitrogen signals indicating a patchy and/or thinner layer of the silicone with an estimated thickness of 4run. XPS Results: De sition of Silicone and Formula Silicone Atom o/o Dis ersion 19.8 0.97 18.9 0.77 The results demonstrate the application method significantly influences the deposition of the silicone and quaternary ammonium salts onto the hair fiber. The direct application shows significantly lower levels of silicone on the hair fiber. However, the conditioner formulation with the polymer still has twice the deposited silicone compared to the formulation without polymer. The amount of quaternary nitrogen appears higher in the hair fibers treated with the conditioner with the polymer, but additional data indicates this may not be significant. In order to confirm the benefits of the nonionic polymer in direct application a combing experiment was conducted. The results of the wet comb show no significant difference between the conditioner with polymer and without the polymer. The dry comb does show a 10% reduction in the tresses exposed to the conditioner with the polymer. InDuence of Nonionic Pol mer on Combin Force Reduction Formula Combin uctlon % 77 53 79 42 Hair fibers treated with the conditioner with and without the polymer were viewed under the electron microscope as shown below: The hair fiber exposed to the conditioner with the polymer shows a smoother cuticle surface and a cementing of the cuticle that is not seen in the conditioner without the polymer. These morphological effects are not influenced by the application method, but their magnitude and extent on the surface is. 467

468 JOURNAL OF COSMETIC SCIENCE THERMOMECHANICAL ANALYSIS OF HAIR FIBERS TREATED WITH KNOWN ACTIVES IN FORMULATIONS K.R. Ramaprasad, Ph.D., Binhua Yang and Yash K. Karnath, Ph.D. TRI/Princeton, PO Box 625, Princeton, NJ 08542 Introduction The constant damages suffered by hair fibers because of diverse grooming practices have their inevitable toll on their strength. The formulations that have been designed to address specific damage issues in the hair care industry need quantitative physical methods to objectively evaluate product efficacy. The relevant mechanical property of hair is a context specific attribute, since improvements claimed do not always ref er to any specific locale in the complex hair structure. Depending on the history of the hair fiber and the chemical structure and size of the active in the formulation, specific location in the hair fiber will be affected. It would be desirable to have complementary methods that would aid in the better understanding of the locale specificity of a successful active. 111.is work reports on initial results from an investigation to understand the way the thennomechanical properties of hair fibers change after application of actives whose location in the hair, when they are applied, is known from literature. Experirnental Bair fibers: All work was performed on yellow bleached hair procured from De Meo Bros., New York. The fibers were all screened so that their cross-sections are in the range of0.00300 to 0.00500 mm2• Actives: The following actives, generally in vogue in hair care formulations, were used: 0.5% solution ofa polyquat-10, 0.5% solution ofCETAB, 1% solution of Panthenol and just deionized water for a control. Treatment protocol: With each solution of the active, the hair fibers were soaked in the solution and kept for 6 h at 40°C. The fibers were then gently rinsed and equilibrated at room ambient (65% RH and 21 ° C) overnight before being mounted for TMA analysis. Instrument: Perkin Elmer Thermomechanical Analyzer, Model TMA 7, was used to make the stress relaxation measurements. Such studies were undertaken at three different temperatures (40 ° , 60° and 80°C). At each temperature, the properly mounted hair fiber (-3 cm long) was allowed to equilibrate with the ambient for 5 min before application of the stress. At the end of this period, a stress of 250 mN was applied and stress relaxation recorded. More than IO fibers were studied, individually, and from this set, only those results were chosen that had a strain value in the region of I - 2 %. 111.is was an attempt to normalize as closely as possible tl1e initial conditions for each fiber in the study. Results and Discussion Only the initial stress relaxation rates have been considered (about 30 s after application of the stress). For each fiber, a first order plot of In S1 vs t gave the rate constant k. Here S1 is the recorded stress at time t. These plots (too numerous) are not shown here. From the set of k values for each active, at each temperature, an average k was calculated. The Arrhenius plot of In k vs 1/f, where T is the temperature in Kelvin at which stress relaxation was carried out, is shown in Fig. I for all the actives studied. It must be pointed out that there is considerable spread in the results and one of the future efforts would be directed towards understanding the TMA protocol for this kind of study so that potential variables contributing to this could be identified and corrected. But, given this stipulation, it is to be observed, from Fig. I, that the fibers treated with different actives do exhibit a distinctly different stress relaxation kinetics depending on the kind of interaction of actives with the fibers. It is to be recalled that prior work published in the literature has established that polyquatemium compounds reside mainly on the hair surface and in the intercuticular regions, whereas the much smaller CET AB molecules and also panthenol diffuse into the cuticular and coritcal domain with time. The untreated control (Fig. 1) shows a (small) negative slope, typical of Arrhenius plots, indicating a small activation energy for stress relaxation under these small strain conditions. But as we