j. Cosmet. Sci., 52, 329-353 (September/October 2001) Papers presented at the Annual Scientific Seminar of the Society of Cosmetic Chemists (Thursday's Program) May 10-11, 2001 Sheraton New Orleans New Orleans, Louisiana 329

330 JOURNAL OF COSMETIC SCIENCE TECHNIQUE FOR EVALUATING GROOMING AND WEATHERING DAMAGE TO HAIR Sidney B. Hornby and Nigel J.P. Winsey Martech Contract Services, Inc., Broomall, PA and Dia-Stron, Ltd., Andover, UK Introduction Some of the damage found in hair is the result of grooming and styling over long periods of time, Perming, bleaching, coloring, and other styling procedures cause additional harm to be added to that caused by sheer wear and tear or weathering of the hair. Since consumers do not want to give up their strenuous styling regimens that can lead to cumulative damage of the hair fibers they are looking for formulations that will nourish, protect, and even 'heal' the hair. Therefore, formulatots are constantly challenged to create products that can mitigate damage and promote strong bouncy hair, We have developed a technique to follow the changes in the hair fiber modulus as a function of accumulated stress. The rigors of grooming and styling were simulated on hair fibers using the Cyclic Tester (Dia-Stron, Ltd.) which has being developed to apply repeated tensile stresses that hair fibers can experience during combing or brushing. In this method one end of a hair fiber is attached to a sensitive load cell and the other to a sophisticated drive system that employs a closed loop controlled linear actuator. This drive system can be programmed to achieve a wide range of movement distances, speeds and accelerations and is capable of positional accuracy of better than 10 microns. A schematic diagram of the cyclic tester is shown in Figure 1. Dia-Stron Cyclic Tester Relaxed Hair Fiber no Load • Load Cell Hair Fiber Loaded Moving arm Internal Schematic Fig. 1 Schematic diagram of the Cyclic Tester. Computer During load cycling selected load-elongation curves of the fiber can recorded by the computer for subsequent analysis. The computer also records the number of cycles that have elapsed if a fiber should break during the test. We can subsequently analyze the accumulated failure data and monitor changes in the hair fiber modulus and resilience.