ANTI-POLLUTION
the hair’s protein matrix was 233.09°C in the control sample and greater than 250°C when the hair was washed with the EDDS containing shampoo. These values show that the hair fibre’s matrix is more damaged by UV radiation in the control than the hair washed with the shampoo containing EDDS as less heat is required to degrade the hair’s protein matrix in the control samples.
Colour testing using CIE L*a*b* Hair switches were soaked in a 5% copper sulphate solution for 24 hours to ensure enough copper penetrated the hair and caused a colour change.
The hair switches were measured before
washing, after washing and after UV treatment using a Sheen Instruments Micromatch Plus handheld colour meter with a 4mm viewing area at the top, middle and bottom of the switch, before the values were averaged over three switches to produce L*a*b* values which were then compared to previous L*a*b* values. ∆E was calculated using the CIE76 and values above 2 are accepted to be a perceivable difference in the measured colours. The first set of colour measurements taken
after washing 60 times with or without a shampoo containing EDDS show a difference in a value. The a value in CIE L*a*b* relates to the amount of green (negative values) or red (positive values) in the measured colour. Figure 5 shows that the amount of green
colour in the hair sample washed with EDDS was less than in the sample washed without EDDS, showing that copper was removed more effectively in the EDDS shampoo samples. The hair switches were then exposed to
UV radiation for 48 hours before the colour was measured and ∆E was calculated in comparison to the washed samples which had not undergone UV exposure. As shown in Figure 6, there was a
perceivable change in the colour of the hair in the sample washed with the control shampoo, however there was not a perceivable difference in colour after exposure to UV radiation in the hair switches which were washed with the EDDS containing shampoo. The colour changes observed suggest that the melanins in the hair treated with the control shampoo is more negatively affected by the UV
2.00 1.50 1.00 0.50 0.00
-0.50 -1.00 -1.50
-2.00 -2.50 -3.00
Washed with EDDS Washed without EDDS
Figure 5: The change in a value measured after 60 washes with and without an EDDS containing shampoo
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Figure 6: The colour change (∆E) of virgin brown hair after washing with and without an EDDS containing shampoo and being exposed to UV radiation for 48 hours
October 2025 PERSONAL CARE
0.2 0.0
-0.2 -0.4 -0.6 -0.8
0 Exo Up 50 100 150 Temperature T (°C)
Figure 3: A DSC trace showing the denaturation of the protein matrix occurring at 233.09°C after 60 washes with the control shampoo and UV exposure
0.2 0.0 -0.2 -0.4
-0.6 Exo Up
Enthalpy (normalised): 6.3785 J/g Onset x: 228.71°C
55
Peak temperature: 233.09°C 200 250
0
50
100
150 Temperature T (°C)
Figure 4: A DSC trace showing the denaturation of the protein matrix occurring at >250°C after 60 washes with the EDDS shampoo and UV exposure
radiation than the melanins in the hair samples which were washed with the EDDS shampoo.
Fourier transform infrared spectroscopy (FTIR) FTIR is a common and non-destructive method for determining the amount of cysteic acid present in hair switches after subjecting them to oxidative damage. The most characteristic peaks relating to cysteic acid in hair are at 1040 cm-1, where the symmetric stretching of cysteic
7 6 5 4 3 2 1
0 Switch ave brown EDDS after UV Switch ave brown no EDDS after UV
acid can be detected.15 When analysing the UV damaged hair
switches, bleached hair and virgin unexposed hair were used as controls to show highly damaged or minimally damaged hair. Three spectra were taken from both washed hair conditions, and their peak areas at 1040 cm-1 were compared. The mean areas of the peaks were
compared, and the hair washed with the EDDS containing shampoo was found to have a
200
250
300
*a Value
Heat flow (normalized) Q (W/g)
Heat flow (normalized) Q (W/g)
Colour change, ∆E
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