A Diester to Protect Hair from Color Fade and ... - Alluredbooks.com

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418 Chapter 35 Gao et al. on the treated tresses using a spectrocolorimeter c . The equation used to calculate the total color loss was: ∆E = [(∆L) 2 + (∆a) 2 + (∆b) 2 ] 1/2 Formula 1. Shampoo test formulations Ingredient Control Diester Shampoo Sodium laureth sulfate 35.00% w/w 35.00% w/w Cocamidopropyl betaine 10.00 10.00 Quaternium-95 (and) propanediol, 75% active (ChromaVeil, Croda) --- 2.00 peG-150 pentaerythrityl tetrastearate (and) peG-6 caprylic/capric glycerides (and) water (aqua) --- 2.80 Water (aqua) 55.00 50.20 100.00 100.00 Formula 2. Conditioner test formulations Ingredient Control Diester Conditioner Conditioner Quaternium-91 (and) cetrimonium methosulfate (and) cetearyl alcohol 2.14% w/w 2.14% w/w Cetearyl alcohol 3.86 3.86 Quaternium-95 (and) propanediol, 75% active (ChromaVeil, Croda) --- 2.00 phenoxyethanol (and) methylparaben (and) ethylparaben (and) butylparaben (and) propylparaben (and) isobutylparaben (phenonip, Clariant) 1.00 1.00 Water (aqua) 93.00 91.00 100.00 100.00 The changes in hair color indexes were calculated using the respective values after the shampoo and conditioner treatments and before UV exposure; and after the equivalent of 15 days of UV c LabScan Xe Spectrocolorimeter is a product of hunterLab.
419 A Diester to Protect Hair from Color Fade and Sun Damage exposure. The results of the instrumental evaluations were confirmed via subjective testing. The swatches were photographed and compared to dyed but untreated swatches, which represent the initial dye color, to allow for visual comparisons. Panelists were also asked to rate the color protection effects in simple comparisons of the control and the diester swatches to the untreated control. To determine the amount of damage on the hair fiber due to the UVB irradiation, several parameters of the hair fiber were measured. As noted, UV exposure to hair can break down the disulfide bonds in the hair fiber. Tryptophan is a key amino acid found on the hair surface and it decomposes under UVB irradiation. 2 Surface tryptophan degradation is thus an indicator of damage to the disulfide bonds and it can be quantified through comparative fluorescence intensities of hair tresses using a spectrofluorometer d . The excitation wavelength was set at 295 nm and the tryptophan emission intensity was measured at 340 nm. The emission intensity was assumed to be directly proportional to the surface tryptophan concentration. Using surface tryptophan intensities of the hair sample before UV exposure as the baseline, the tryptophan protection factors of hair samples treated with diester shampoo or the control shampoo after UV exposure can be calculated using the equation: F (Tr) = [I f / I o ] X 100% In this equation, F(Tr) is the tryptophan protection factor, calculated as a percentage; I f is the surface tryptophan fluorescence intensity of the hair sample after UV exposure; and I o is the surface tryptophan fluorescence intensity of the same hair sample before UV exposure. UVB rays not only decompose the surface tryptophan but also penetrate the hair cuticle and cause damage inside the cortex. This damage affects hair’s mechanical properties and can be measured in terms of its tensile strength (stress-to-break). Using a tensile tester e , the tensile strength of single fibers from the treated tresses was measured before and after UV exposure. d Spex FluoroLog-3 is a instrument manufactured by horiba Jobin Yvon. e Miniature tensile tester (Mtt) 670 is a product of Dia-Stron Ltd.
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A Diester to Protect Hair from Color Fade and ... - Alluredbooks.com

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