Microwave extraction of eucalyptus natural dyes and dyeing of wool

Microwave extraction of eucalyptus natural dyes and dyeing of wool

Zhang Yuping ^1, Yuan Dehong ^{1, 2} OF CRITICAL

( 1. Nantong Vocational University, Nantong 226007, China; 2. School of Textile and Clothing, Nantong University, Nantong, Jiangsu 226019, China )

Abstract: The conditions of microwave extraction of natural dyes of eucalyptus leaves and the conditions for dyeing wool were optimized. The effects of sodium hydroxide dosage, microwave power and irradiation time on the extraction efficiency were discussed. The effects of dyeing pH, dyeing temperature, time and sodium sulfate dosage on the dyeing effect were also discussed. The optimization process of microwave extraction is: sodium hydroxide 0.25mol/L, microwave power 595W, extraction time 11min, and the ratio of material to liquid is 1:20. The optimum process for the direct dyeing of the extract by the extract is: pH of the dye solution is about 5, the dyeing temperature is 100 ° C, the time is 60 min, and the bath ratio is 50:1. Wool has a certain degree of fastness after dyeing with eucalyptus leaves extract, and mordant dyeing can appropriately improve the dyeing fastness.

Key words: eucalyptus leaves; natural dyes; wool; dyeing

CLC number: TQ611 Document code: B

Microwave Extraction of Natural Dye

From Camphor Leaves and Its Dyeing on Wool Fabric

ZhANG Yu-ping ¹ , YUAN De-hong ¹ , CHEN Mei-yun ²

(1. Nantong Vocational College, Nantong 226007, China;

2. College of Textile and Clothing, Nantong University, Nantong 226019, China)

Abstract: Microwave extraction conditions for natural dye from camphor leaves and the dyeing conditions on wool fabrics with resulting extract were optimized. Factors exerting influence on extraction results such as NaOH concentration,microwave power , extraction time, and factors exerting influence on dyeing results on wool单词 NaOH 0.25mol/L, microwave power 595w, extraction time 11min, solid to fabrics such as dyeing pH, dyeing temperature, dyeing time, Na ₂ SO ₄ concentration were discussed. It was found that the optimum conditions for the extraction were as follows: NaOH 0.25mol/L, microwave power 595w, extraction time 11min, solid to The optimum conditions for the dyeing on wool fabrics were as follows: pH value 5, dyeing temperature 100°C, dyeing time 60min, bath ratio 50:1. The dyed wool fabrics with resulting extract had definite fastness and the fastnesses Properties could be improved by mordanting.

Keywords: camphor leaves, natural dyes, wool fabric, dyeing

Natural dyes, especially plant dyes, are environmentally friendly, renewable, and health-care, and are receiving more and more attention. The camphor tree is a subtropical tree species, mainly distributed in the south of the Yangtze River. It is known as the Jiangnan Baoshu. It is an excellent street tree and shade tree. It is also an ideal material for luxury furniture, high-end buildings, shipbuilding and sculpture. Eucalyptus leaves can be used for pesticides, spices, feeds, etc. ^{[1,2 ]} , eucalyptus leaves, can cure gastroenteritis, stomach cold and abdominal pain, indigestion, whooping cough, dysentery, can also treat rheumatoid arthritis, malaria, beaten Injury ^[3] has a significant effect on the treatment of coronary heart disease, cerebral thrombosis and the elimination of free radicals ^[4] . There are also many types of eucalyptus leaves, such as red pigment, green pigment, brown melanin, etc. The extracted pigments can be used in the food industry. The extraction methods and properties have been reported in small amounts ^{[5 , 6]} , but the pigments are used for textile dyeing. Only mentioned on Huang Ronghua's website, no other research reports have been reported.

Microwave generally refers to electromagnetic waves with a frequency between 300 and 300,000 MHz and a wavelength of 1 mm to 1 m. Microwave-assisted extraction of natural plant dyes has the characteristics of low energy consumption, high extraction efficiency, good reproducibility and low pollution. This paper mainly discusses the process of extracting natural dyes from eucalyptus leaves under microwave irradiation, and discusses the dyeing process of eucalyptus leaves extract on wool fabrics, and determines the dyeing fastness of dyed wool fabrics.

1, the test part

1.1 Test materials, drugs and instruments

Test material: wool fiber woven plain weave fabric.

Test drugs: sodium hydroxide, sodium carbonate, hydrochloric acid, anhydrous sodium sulfate, copper sulfate, potassium aluminum sulfate, ferrous sulfate, etc., all of which are of analytical grade. The eucalyptus leaves were collected from Youth East Road, Nantong City, Jiangsu Province in August 2009. .

Instruments and equipment: PHS-3C precision pH meter (Shanghai Precision Scientific Instrument Co., Ltd.), Color- Eye3100 color measurement and color matching instrument (Libao Scientific Equipment Co., Ltd.), TU-1901 dual-beam UV-visible spectrophotometer (Beijing Pu analysis General Instrument Co., Ltd.), GYROWASH415 Washing/Dry Cleaning Color Fastness Machine (UK), Y(B)571-II Preset Color Fastness Friction Instrument (Wenzhou Darong Textile Standard Instrument Factory), SHA-C water bath constant temperature oscillation (Jintan Hengfeng Instrument Factory) .

1.2 Test methods

1.2.1 Microwave extraction of natural dyes from eucalyptus leaves

Sodium hydroxide 0.2 ~ 0.4mol / L, microwave power 189 ~ 595W, radiation time 1 ~ 12min, ratio of material to liquid 1:10 ~ 1:50. The eucalyptus leaves washed and dried and pulverized are weighed, added to the sodium hydroxide solution of the desired concentration, wetted, adjusted to the specified power, extracted within a prescribed time, cooled, and filtered.

1.2.2 Direct dyeing of wool by eucalyptus leaves extract

Eucalyptus leaves 5 ~ 20g / L, dyeing solution pH 3.00 ~ 9.00, sodium sulfate 0 ~ 50g / L, dyeing temperature 40 ~ 100 ° C, dyeing time 15 ~ 120min, bath ratio 50: 1. Prepare the dyeing solution according to the requirements, adjust the dyeing pH value, put the fully wetted wool into the dyeing solution at room temperature, raise the temperature to the specified temperature, add sodium sulfate for 30 minutes, continue dyeing for a certain time at this temperature, and cool it to dry.

1.2.3 Woven mord dyeing

Pre-media dyeing: mordant dyeing → dyeing → washing and drying.

Same medium dyeing: Directly put the wool into the dyeing solution containing mordant and eucalyptus leaves dyeing, dyeing according to the optimized direct dyeing process, cooling and drying.

Post-media dyeing: dyeing→mord dyeing→washing and drying.

Mordant prescription: mordant 1 ~ 9g / L, temperature 40 ~ 80 ° C, time 15 ~ 120 min, bath ratio 50: 1.

1.3 performance test

1.3.1 Absorbance of eucalyptus leaves extract

The measurement was carried out in the range of 200 to 800 nm using a TU-1800 SPC ultraviolet/visible spectrophotometer.

1.3.2 K/S value, L ^* , a ^* , b ^* value of dyed wool

It was measured at the maximum reflection wavelength of the dyed wool on a Color-Eye 3100 colorimetric colorimeter.

1.3.3 Test of color fastness

The rubbing fastness is determined according to GB/T3920-1997 "Color fastness to abrasion of textile color fastness test"; the washing fastness is according to GB/T3921.1-1997 "Color fastness test of textile color fastness: test 1" Determination.

2 , results and discussion

2.1 Analysis of extraction process factors of natural dyes from eucalyptus leaves

2.1.1 Effect of extraction time and power on the extraction effect of eucalyptus leaves

The ratio of fixed material to liquid is 1:30, the amount of sodium hydroxide is 0.3mol/L, only the irradiation time or power is changed. The extraction power is 189, 259, 280, 462W, respectively, and the extraction time is 1, 2, 3, 4, 5, respectively. 6, 7, 8, 9, 10, 11, 12 minutes. The absorption wavelength and absorbance of the extract are shown in Table 1.

Table 1 Effect of microwave power and irradiation time on the maximum absorption wavelength and absorbance of eucalyptus leaves extract

It can be seen from Table 1 that the microwave power and irradiation time have little effect on the maximum absorption wavelength of the extract. The maximum absorption wavelength of the extract is in the range of 212 nm to 214 nm. With the increase of microwave power and irradiation time, the absorbance of the extract increases.

2.1.2 Orthogonal test optimization extraction process

Four factors including sodium hydroxide dosage, microwave power, extraction time and solid-liquid ratio were selected. Three factors were selected for each factor for L ₉ (3 ⁴ ) orthogonal test. The orthogonal test protocol, the absorbance of the extract (213 nm) and the results are shown in Table 2.

Table 2 L ₉ (3 ⁴ ) orthogonal test scheme, results and analysis

It can be seen from Table 2 that the microwave power has the greatest influence on the absorbance of the extract, followed by the ratio of material to liquid and the amount of sodium hydroxide, and the influence of microwave irradiation time is small. Among the microwave power, level 3 works best, followed by level 1 and level 2, the ratio of material to liquid and sodium hydroxide is the best, and the level of microwave irradiation is 2 is the best . Therefore, the microwave extraction optimization process of eucalyptus leaves natural dye is: 0.25mol/L sodium hydroxide, 595W microwave power, extraction time 11min, and the ratio of material to liquid is 1:20.

2.2 Analysis of the factors of wool direct dyeing process

2.2.1 Single factor test of wool direct dyeing

2.2.1.1 Effect of dyeing pH on dyeing effect

Fixed eucalyptus leaves 10g / L, dyeing temperature 100 ° C, time 60min, bath ratio 50:1, adjust the dye pH value of 2.03, 3.03, 4.03, 5.03, 6.00, 7.00, 8.03, 9.00, 10.00, eucalyptus leaves extract The K/S value of dyed wool is shown in Figure 1.

Figure 1 Effect of dyeing pH on wool dyeing effect

It can be seen from Fig. 1 that the pH is between 2 and 3. As the pH value of the dyeing solution increases, the K/S value of the dyed wool gradually increases, and the dyeing pH is greater than 3. As the pH increases, the dyed wool The K/S value gradually decreased, and the leveling property was poor due to the pH value of the dye solution being less than 5. Therefore, it is appropriate to select a dyeing pH of about 5.00.

2.2.1.2 Effect of dyeing temperature on dyeing effect

Fixed eucalyptus leaves 10g/L, dyeing solution pH 5.01, dyeing time 60min, bath ratio 50:1, dyeing temperature 40, 50, 60, 70, 80, 90, 100 ° C, eucalyptus leaves extract dyeing wool K The /S value is shown in Figure 2.

Figure 2 Effect of dyeing temperature on wool dyeing effect

It can be seen from Fig. 2 that as the dyeing temperature increases, the K/S value of the dyed wool increases and reaches a maximum at 100 ° C, so the dyeing temperature is selected to be 100 ° C.

2.2.1.3 Effect of dyeing time on dyeing effect

Fixed eucalyptus leaves 10g / L, dyeing liquid pH value 5.01, dyeing temperature 100 ° C, bath ratio 50:1, dyeing time is 15, 30, 45, 60, 75, 90, 105, 120min, eucalyptus leaves extract dyeing wool The K/S value is shown in Figure 3.

Figure 3 Effect of dyeing time on wool dyeing effect

It can be seen from Fig. 3 that the K/S value of dyed wool increases gradually with the increase of dyeing time. After 60 min, the K/S value of dyed wool decreases or even decreases slightly. Considering the dyeing time, 60 min is selected. .

2.2.1.4 Effect of sodium sulfate dosage on dyeing effect

The eucalyptus leaves were fixed at 10 g/L, the pH of the dyeing solution was 5.01, the dyeing temperature was 100 ° C, the dyeing time was 60 min, and the bath ratio was 50:1. The amount of sodium sulfate used was 0, 10, 20, 30, 40, 50 g/L, respectively. The K/S value of the dyed wool of the eucalyptus leaves extract is shown in Fig. 4.

Figure 4 Effect of sodium sulfate dosage on wool dyeing effect

It can be seen from Fig. 4 that the amount of sodium sulfate has little effect on the dyeing of wool, so that sodium sulfate may not be added during dyeing.

2.2.1.5 Effect of dye dosage on dyeing effect

The fixed dyeing solution has a pH of 5.01, a dyeing temperature of 100 ° C, a time of 60 min, a bath ratio of 50:1, and a eucalyptus leaf dosage of 5, 10, 15, and 20 g/L, respectively. The K/S value of the eucalyptus leaf extract dyed wool is as follows. Figure 5.

Figure 5 Effect of the amount of dye on the dyeing effect of wool

It can be seen from Table 3 that for the dyed wool K/S value, the pH value has the greatest influence on the dyeing effect, followed by the amount of eucalyptus leaves, the dyeing temperature and time. The dyeing pH value is best at level 1, the eucalyptus leaf dosage, dyeing temperature and time are all at level 3; for the lightness L ^* value of dyed wool, the effect of wool dyeing effect from primary to secondary is dyeing temperature and pH. Value, amount of eucalyptus leaves, dyeing time; the most important effect on shade is pH. Because the K/S value of dyed wool is the most important performance index to measure the dyeing effect, the results of comprehensive single factor and orthogonal test, considering the pH value is not easy to level dye, so the dyeing pH is 5.00, and the dyeing temperature is 100 °C. Well, the influence of dyeing time is the smallest, so it can be used for 60 min, and the dye lifting property is good. It can be selected according to the needs. The following test takes 10 g/L.

2.3 Effect of mordant dyeing on wool dyeing effect

The wool was pre-mord, mordant and post-mord dyed with copper sulfate, ferrous sulfate and aluminum aluminum sulfate. The K/S, L ^* , a ^* and b ^* values ​​of the dyed wool are shown in Table 4.

Table 4 Effect of mordant method on dyeing effect

Note: The dyeing method is an optimized conventional dyeing process;

The mordant conditions are as follows:

Copper sulfate 1g/L, mordant temperature is 70 ° C, mordant time is 45 min, bath ratio is 50:1.

Ferrous sulfate 3g / L, mordant temperature is 50 ° C, mordant time is 45 min, bath ratio 50:1.

Potassium aluminum sulfate 1g / L, mordant temperature 50 ° C, mordant time 30 min, bath ratio 50:1.

It can be seen from Table 4 that different mordants and different mordant methods have different effects on the dyeing effect of wool. After the copper sulphate mordant dyeing, the K/S of the dyed wool increased, the brightness decreased, and the K/S value of the pre-media increased the most; the pre-media increased the red light of the dyed wool, while the same medium and the latter decreased slightly; the same medium made the dyed wool The yellow light increases, while the pre-media and post-mord dyes cause the yellow light to fall. After the ferrous sulfate mordant dyeing, the K/S of the dyed wool increased, the brightness decreased, and the K/S value of the dye increased the most; the mordant dyed the red and yellow light of the dyed wool significantly decreased. The mordant effect of aluminum sulphate was not as obvious as that of copper sulphate and ferrous sulphate. The K/S of dyed wool increased after pre-media, and the brightness decreased, while the K/S decreased slightly. The same media had little effect; dyeing wool after mordant dyeing The yellow light increased significantly; the red light of the pre-media and the same medium dyed wool increased, but the post-media decreased.

2.4 Dyeing fastness of dyed wool

The dyeing cloth was the same as 2.3, and the dyeing fastness of the dyed wool was measured. The results are shown in Table 5.

Table 5 Color fastness of dyed wool