Physical and mechanical properties of Tunisian women hair.

BACKGROUND: Mechanical analysis of human hair may provide the dermatologists with several markers of considerable diagnostic importance. The aim of this study was to analyse the physical and mechanical properties of Tunisian women's hair. METHODS: Surface characteristics were determined with scanning electron microscopy (SEM). Mechanical properties were studied using the Miniature Tensile Tester Model 675 (MTT675), and the Fibre Dimensional Analysis Unit Model 765 (FDAS765) of Dia-Stron, UK, was used to measure the cross-sectional area. RESULTS: The cross-sectional area, stress at break, strain at break, elastic modulus and total work were 4643.21 ± 817 µm(2) , 201 ± 11.26 MPa, 47.3 ± 3.6%, 3.1 ± 0.16 GPa, and 9 ± 2.2 mJ, respectively. The effects of the factors 'hair curliness' and 'age' on the physical and mechanical properties were studied. The cross-sectional area and the break load are influenced by the factors 'age' and 'curl type', whereas Young's modulus shows a significant dependency only on the age. CONCLUSION: Tunisian women hair presented good mechanical properties as shown by a greater breaking stress and higher breaking strain. Both curl type and age are important factors to consider when evaluating the behaviour of hair.

Ultrasonic preparation of cationic cotton and its application in ultrasonic natural dyeing.

Cationization of cotton fabric was conferred by the sonicator reaction of cellulose with bromoacetyl bromide, followed by substitution of the terminal bromo groups by triethylamine. Experiments showed that the optimal volume of bromoacetyl bromide necessary to succeed the first stage was 0.4 mL. The order of weight gain for various processes indicates, ultrasound, 25 kHz> ultrasound, 40 kHz> mechanical stirring. Also, for the second stage the order of nitrogen contents indicates ultrasound, 25 kHz> ultrasound, 40 kHz> mechanical stirring. The structures of both untreated and cationic fibres were investigated by FTIR spectroscopy. Modified cotton fabric was subsequently dyed in both conventional and ultrasonic techniques with isosalipurposide dye isolated from Acacia cyanophylla yellow flowers. The effect of dye bath pH, ultrasonic power and frequency, dyeing time and temperature were studied and the order of K/S values indicates ultrasound, 25 kHz > ultrasound, 40 kHz > CH. ultrasound was also found to enhance the dye uptake and the overall fastness properties. Analysis of the sorption isotherms of isosalipurposide dye on cationic cotton fabric shows that the Languimir isotherm equation is best able to correlate the data.