2006 TRI/PRINCETON CONFERENCE 407 POSTTREATMENT OF RELAXED HAIR Lithium relaxer cream (0.4g) was applied to the afro hair switch (0. lg) and massaged in until it was well covered. The cream was left for 20 minutes and tension was applied by massaging 10 times at 5 minute intervals. The hair was rinsed in water at 40°C for 2 minutes. The switch was then washed with 0.4g of neutralizing shampoo and rinsed. The switch was either left in water (control) or placed in an aqueous solution of 1 % functional keratin (as supplied) for 2 minutes, rinsed and allowed to dry overnight. Mechanical testing was carried out on 50 hair fibers randomly sampled from each of the switches. Fibers were wet for at least 30 minutes prior to measurement. Each fiber was placed in the grips of the tensile tester (Instron 4204). Individual hair fibers were extended at a constant rate (100%/min) until rupture and the force was recorded. COLOR PROTECTION Virgin human hair (De Meo, natural red) was dyed with Colour Cream and developer Perfectone 66/46 Cherry Red (Wella) using the procedure described on the packet. All hair was dyed together according to the instructions (12.5g of color cream was mixed with 10g of color cream developer). The mixture was applied to the hair, completely covering the sample and left for 30 minutes for color development. The hair was then washed in 40°C water until no further color washed out. The hair sample was air dried and separated into 3g tresses. The treatment conditions were: Control-dyed and exposed UV light and washing. Keratin treated-dyed, treated with a conditioner base containing 1 % functional keratin (using a rinse-off protocol) prior to exposure to UV light, and washing. Conditioner base treated-dyed, treated with conditioner base prior to UV light exposure, and washing. All tresses were washed prior to and following 24 hrs of UV exposure (MBTF 1 000W lamp in a light box). Conditioner with 1 % functional keratin or the base was applied prior to each 24 hr UV exposure, using a rinse off protocol. 24 hours of UV is the equivalent to -10 days of New Zealand summer sunlight. The application, UV, washing procedure was repeated 3 times to give a total of 72 hrs of UV light exposure. L*a*b* measurements were made at each 24 hr interval. RES UL TS AND DISCUSSION HAIR SOFTNESS Moisture is a significant factor in hair softness. Dry hair is brittle, and feels coarse compared with soft hair which has greater flexibility and can accommodate bending and extension more easily. Panel assessment involving 12 volunteers showed that addition of functional keratin to a conditioner gave hair a softer feel (see Figure 1). This increase in softness arises from ability of the functional keratin to protect the natural structure of the hair, and in doing so assist the hair in retaining moisture.

408 en C en ._ "D cu ::s = ·-o f rn cu cu .a ... 0 C .,. ::::I rn 0 rn !! 0 ... ';ft. 80 70 60 50 40 30 20 10 0 JOURNAL OF COSMETIC SCIENCE 95% significant Untreated Base conditioner Conditioner + 1 % functional keratin Figure 1. Graph showing the results of a volunteer panel assessment of hair softness comparing untreated, base conditioner treated and conditioner plus 1 % functional keratin treated hair tresses. HAIR BREAKAGE Hair breakage results from the deterioration of the fiber structure and poor grooming practises. Hair tresses either untreated, or conditioner treated with and without keratin, were prepared and repeatedly combed, as described in the methods section. Only a small amount of breakage was found after the first 400 strokes, with 16 fibers counted for the water control, 10 for the conditioner formulation and 7 for the conditioner plus the functional keratin, indicating that the hair used was in a relatively undamaged state. A further 1200 strokes were performed to stress the hair. The total number of fibers broken for each condition is summarized in Figure 2. Following this protocol it was found that C rn a, cu .=-: e e .Cl ... en rn e � .a·- .a ._ E ·- 0 � u 11-0 0 c:, ._ ca .z : E! :::::, ca z 1200 1000 soo- 600 400 200 0 Untreated Base Conditioner + conditioner 1 % functional keratin Figure 2. Total number of broken fibers collected following 1600 combing strokes for tresses treated with water (control), base conditioner, and conditioner plus 1 % functional keratin.