2009 Volume 58 Issue 8 Pages 667-673
The water content of hair was measured by a dry-weight method, and was predicted by multiple-regression analysis using near-infrared (NIR) spectrum data after a spectra-pre-treatment. The correlation between the value by the dry-weight method and the NIR predicted value was r2 = 0.957, and indicated that predicting the water content of hair from the NIR spectrum data is possible. In addition, we obtained the formula ∂(lnw)/∂(1/T) = ΔH/R (w, water content ; ΔH, vaporization enthalpy change) by an analogy of the Clausius-Clapeyron equation, and we proposed that the individual variability of the moisture in hair (difficulty in evaporation of the water in the hair) is the difference in the vaporization enthalpy. The water content of the hair at 20∼100°C was measured for 10 people (21∼23 years old), and ΔH was obtained from the slope of plots of (ln [w/mol/kg]) vs. (1/T). As a result, the capacity of moisture in hair could be suggested by comparing it with ΔH (43.991 kJ/mol) of pure water.
