AUTEX Research Journal, Vol. 9, No1, March 2009 © AUTEX SOME STUDIES ON DYEING PROPERTIES OF COTTON FABRICS WITH CROCUS SATIVUS (SAFFRON) (FLOWERS) USING AN ULTRASONIC METHOD M.M. Kamel, H.M. Helmy, and N.S. El Hawary National Research Centre, Textile Research Division, Dokki, Cairo, Egypt, E-mail: [email protected] Abstract: Cotton fabrics were dyed with natural colouring matter extracted from Crocus sativus (saffron) using a traditional heating method and a power ultrasonic method. Factors affecting the dyeing properties such as pH values, salt concentration, temperature, duration of dyeing bath, and ultrasonic power were studied. Environmentally friendly mordants were used in pre-mordanting, post-mordanting, and simultaneous-mordanting methods. The fastness properties including light, washing, and perspiration of dyed and mordanted fabrics were assessed. Colour strength (K/S) was measured for dyed and dyed mordanted cotton fabrics. Key words: Dyeing, cotton fabrics, saffron, ultrasonic energy 1. Introduction powder in 100 ml water at the boil for one hour, after which the solution was filtered off and left to cool down. There are only two or three places in the world where Crocus sativus (saffron) grows. Kashmir has the proud privilege of 2.2.2. Dyeing methods being one of these places. The Crocus sativus (saffron) plant Dyeing of cotton fabrics using traditional method is very small and its flower is the only part which is seen above the ground. The blooming time of this flower is autumn. Cotton fabric samples (0.5 g each) were dyed with the natural Crocus sativus (saffron) has a unique sweet smell and it is colouring matter extracted from Crocus sativus (saffron) at a used in dyeing and cooking [13]. liquor ratio of 1:50. Dyeing was carried out at different pH In this work a natural dye was extracted from Crocus sativus values (3–8) using different concentrations of sodium powder [5–6]. The effects of concentration of colouring matter, chloride, dyeing durations, and temperatures as in the text. salt, different mordant types with different methods, pH, The fabric samples were immersed in the dyeing solution in temperature, duration of dyeing bath, and ultrasonic power a water bath at 40 °C. The fabrics were dyed for different were studied for both the traditional method and the ultrasonic lengths of time and the dyed samples were rinsed with cold energy method of dyeing. Also, the fastness properties of dyed water and washed for 30 minutes in a bath containing 3 g/L of and simultaneously, pre-, and post-dyed mordanted fabrics non-ionic detergent at 45 °C. Finally, the fabrics were rinsed were evaluated [14–17]. and air dried. 2. Experimental Dyeing of cotton fabrics using ultrasonic energy method 2.1. Materials Cotton fabric samples (0.5 g each) were dyed with the natural 2.1.1. Natural colouring matter colouring matter extracted from Crocus sativus (saffron) at a liquor ratio of 1:50. Dyeing was performed at different pH The colouring substance used in this work was extracted values using different concentrations of sodium chloride, from the Crocus sativus (saffron) plant. dyeing durations, and temperatures as well as different power levels of ultrasonic energy as shown later. The fabrics were 2.1.2. Fabrics immersed in the dyeing solution and subjected to ultrasound Mill-scoured and bleached cotton fabrics (130 g/m2) were at 40 °C for different lengths of time and power levels. Fixation kindly supplied by Misr El Beida Co. Egypt. of the Crocus sativus (saffron) colour was carried out as before. The samples were rinsed with cold water and then 2.1.3. Mordants washed for 30 minutes in a bath containing 3 g/L of non-ionic detergent at 45 °C. Finally, the fabrics were rinsed and air The following mordants were used: potassium aluminium dried. sulphate, copper sulphate, stannous chloride, ferrous sulphate, and tannic acid. They were pure grade chemicals Mordanting of cotton fabrics [8, 9]. The three methods of mordanting (pre-, simultaneous, and 2.2. Methods post-mordanting) were used to dye cotton fabric with natural 2.2.1. Extraction of natural colouring matter from colouring matter extracted from Crocus sativus (saffron) [7, Crocus sativus (saffron) 11, and 12]. Different common mordant salts were used with permitted concentrations which are given in the literature [8] Crocus sativus (saffron) was crushed to the powder form and for environmentally friendly textiles. then the colouring matter was extracted using 2–12g of the http://www.autexrj.org/No1-2009/0266.pdf 29 AUTEX Research Journal, Vol. 9, No1, March 2009 © AUTEX 2.3. Testing Dyeing conditions: Traditional method: boiling for 60 min 2.3.1. Colour measurements of the dyed fabrics [10] at pH 6. Ultrasonic method: 80 °C for 60 min at power level 9 and pH 6. The colour yields of both the dyed and mordant samples were evaluated by the light reflectance technique using a Perkin- 3.1.2. Effect of pH values Elmer UV/V Spectrophotometer (model Lambda 3B). The colour strength (K/S value) was assessed using the Kubelka- Figure 2 shows that the colour strength (K/S) exhibits a Munk equation. gradual increase with increases in the pH value of the dyeing bath from pH 3 to pH 8 irrespective of the method of 2.3.2. Fastness properties dyeing; it is certain that higher K/S values are achieved with the ultrasonic method. Increasing the pH from 3 to 8 is The washing, dry and wet rubbing, acid and alkaline accompanied by higher colour strength until pH 8 is perspiration, and light fastness were evaluated according to reached. standard methods [1–4]. 7 3. Results and discussion Traditional method 6 Ultrasonic method 3.1. Factors affecting dyeing of cotton with a 5 natural dye extracted from Crocus sativus 4 (saffron) in the powder form 3 3.1.1. Concentration of the dye 2 1 The coloured solutions were extracted by boiling different ( K/S) colour strngth amounts of Crocus sativus (flowers) in powder form in a fixed 0 amount of water (100 ml) and used at different pH values for 0123456789 dyeing cotton fabrics according to traditional and ultrasonic pH values methods. The colour strengths (K/S) of the dyed cotton samples were dependent on the concentration of the natural Figure 2. Effect of pH values on the colour strength (K/S) of cotton colouring matter. fabrics dyed by traditional and ultrasonic methods with natural colouring matter extracted from Crocus sativus (flowers) (12gm/ From the results in Fig. 1, it was shown that the colour strength, 100 ml H2O). expressed as K/S, increases with increasing concentration of the natural colouring matter in the dyeing solution within Dyeing conditions: Traditional method: boiling for 60 min, pH the range studied. These results were observed with 3–8. Ultrasonic method: 80 °C for 60 min, power level, traditional and ultrasonic methods after the dyed fabrics were pH 3–8. subjected to washing at 45 °C. 3.1.3. Effect of salt concentration Also, from Fig. 1 it was found that the colour strength of the fabrics dyed using the ultrasonic method was higher than the The colour strengths of dyed and washed samples were colour strength achieved using the traditional method. The measured and the results are shown in Fig. 3. The figure extra vibration and agitation conferred on the dyeing system also shows that the colour strength increases as the salt by use of the ultrasonic energy method may account for this. concentration increases and the colour strength of the fabric It is understandable that vibration and agitation along with dyed using the ultrasonic method is higher than the colour inducing cavitations in the cotton structure enhance dyeing strength achieved by the traditional method. by promoting exhaustion and better dissociation of the dye molecules within the cotton structure. Second, for a given dye concentration, the decrease in K/S values is more striking Traditional method with the traditional than with the ultrasonic energy method, 7 Ultrasonic method suggesting that the latter affords better dye fixation and 6 diffusion than the traditional method. 5 4 3 Traditional 8 2 Ultrasonic 1 6 (K/S) Colour strength 0 4 01234567891011 Conc. of salt (g/L) 2 0 Figure 3. Effect of salt concentration on the colour strength (K/S) of Colour strength ( K/S) strength Colour cotton fabric dyed by traditional and ultrasonic methods with natural 24681012 colouring matter extracted from Crocus sativus (flowers) (12gm/ 100 ml H O). conc. of Crocus sativus ( g/L) 2 Dyeing conditions: Traditional method: boiling for 60 min, pH Figure 1. Effect of concentration of natural colouring matter extracted 8, salt (2–10g/l). Ultrasonic method: 80 °C for 60 min, salt (2– from Crocus sativus (flowers) (2–12gm/100 ml H O) on the colour 2 10g/l), power level 9, pH 8. strength of cotton fabrics dyed by traditional and ultrasonic methods. http://www.autexrj.org/No1-2009/0266.pdf 30 AUTEX Research Journal, Vol. 9, No1, March 2009 © AUTEX 3.1.4. Effect of temperature results are obtained after 60 min with the traditional method. In the case of the ultrasonic method it was found that 50 min The dyeing procedure was continued for one hour at a duration of dyeing is good because it gives better colour temperature varying from 40 to 100 oC in the case of the strength. traditional method and from 40 to 80°C in the case of the ultrasonic method. Dyeing conditions: Traditional method: 100 °C for 40–80 min, pH 8, salt 10 g/l. Ultrasonic method: 70°C for 40–80 From Fig. 4, it can be seen that the colour strength increases min, salt 10 g/l, power level 9, pH 8.