The dyeing of wool, silk, cotton, ramie, nylon, acrylic and polyester fabric by using the extracts from mulberry branches and trunks was tried and the dyeability was studied. While the dyeability of the ethanol-extracts from mulberry is low, that of the water-extracts is high for wool, nylon and silk fabrics. They are dyed brownish and yellowish colours. The obtained colours depend on the extracts concentration in the dye solution, dyeing time, dye solution pH and dyeing temperature. Wool, nylon and silk fabrics are dyed deeper with an increase in the dyeing temperature. The mulberry extracts show fluorescence and reducing property. The results indicate that the mulberry extracts contain flavonols such as morin, kaempferol or quercetin, which form complexes with Al3+ and show fluorescence. The wool treated with the mulberry extracts or AlCl3/mulberry extracts shows fluorescence with ultraviolet light irradiation.
Mulberry (Morus) trees belonging to the family of Moraceae are important plants that have been used for sericulture to produce silk fibres as it is generally well known. The leaves, fruits and root barks of mulberry trees have long been used widely in the field of silk production, food industries and medicines [
The exploitation and development of novel sustainable dyestuff materials and the effective utilization of industrial wastes are very important to establish a sustainable society and achieve environmental preservation. Under such a situation, the authors tried to dye fabrics with mulberry extracts in the study. The dyeing of fabrics by using a dyestuff obtained from waste mulberry branches and trunks has not been studied aiming to apply the dyestuff to industrial uses. If a useful dyestuff could be obtained from the mulberry extracts, it is expected that the technique will contribute to the efficient use of mulberry wastes. The characteristics of mulberry trees are as follows: 1) the photosynthetic rate and the growing rate of tree are high [
In the study, the dyeability of the extracts from mulberry branches and trunks for natural and chemical fibres such as wool, silk, cotton, ramie, nylon, acrylic and polyester fabrics was investigated as a first step. The properties of the mulberry extracts were also examined.
The mulberry branches and trunks (Morus australis and Morus lhou) were obtained from the mulberry field of Kyoto Institute of Technology. The woods with barks were crashed by a mill (Osaka Chemical Wonder Blender WB-1) and were extracted with ethanol (purity: 99.5%) at 78˚C or distilled water at 100˚C for 4 h. The extracts were concentrated and dried. The dried mulberry extracts were ground into powder.
The wool fabric (tropical, Shikisensha), silk fabric (Kinu Habutai, Shikisensha, basis weight: 52.5 g∙m−2, fabric count: 135 × 98 per inch, plain weave), cotton fabric (broad, Shikisensha), ramie fabric (broad, Shikisensha), nylon fabric (tafta, Shikisensha, basis weight: 60.4 g∙m−2, fabric count: 108 × 82 per inch, plain weave), acrylic fabric (muslin, Shikisensha) and polyester fabric (tafta, Shikisensha, basis weight: 71.8 g∙m−2, fabric count: 120 × 90 per inch, plain weave) were cut into 5 cm squares and used for the dyeing experiments.
The oily mulberry extracts (0.50 g), which were obtained from the extraction with ethanol, were dissolved into 49.5 g of ethanol/distilled water mixed solvent (1:1 of mass ratio). Wool fabric sample was immersed first into distilled water at room temperature (RT) for 10 s and then into the mulberry extracts solution at 40˚C for 3 h. The dyebath was shaken at 80 strokes per minute. The powder mulberry extracts, which were obtained from the extraction with distilled water, were dissolved into distilled water to prepare 2.0 wt% solution. Each of the fabric samples was immersed first into distilled water at RT for 10 s and then into the mulberry extracts solution at fixed temperature (30˚C - 90˚C) for 3 h. The dyebath was shaken at 80 strokes per minute. The liquor ratios were 179:1 for silk, 66.0:1 for wool, 90.6:1 for cotton, 80.1:1 for ramie, 160:1 for nylon, 108:1 for acrylic and 157:1 for polyester. Each of the fabric was washed with 50 ml of 2.0 wt% marseille soup solution at 40˚C for 10 min, rinsed with 100 ml of distilled water at 40˚C for 5 min twice and air-dried.
The obtained colour of the fabric samples was measured by using a Konica Minolta CM-2600d spectrocolourimeter and the resulting colour was expressed in L*a*b* standard colourimetric system (CIE 1976). The colour measurements were made employing CIE standard illuminant D65, 10˚-view angle and SCI (specular component included) mode. All the reflected lights from the sample including the regular reflection are integrated under the SCI mode. The a* and b* are the chromaticity coordinates, and L* is the lightness index in the L*a*b* system. The positive values of a* indicate reddish colours and the negative values of that indicate greenish ones, and the positive values of b* indicate yellowish and the negative values indicate bluish. The C* is the chroma calculated as C* = {(a*)2 + (b*)2}1/2 [
The measurements of the ultraviolet-visible (UV-Vis) light absorption spectra for the mulberry extracts aqueous solutions were made by a Hitachi U-3900H spectrophotometer at RT. The sample solutions were prepared by dissolving mulberry extracts powders into freshly distilled water. Acidic or basic mulberry extracts solution was prepared by dissolving the powder into 2.0 × 10−2 M citric acid aqueous solution or 1.0 M Na2CO3/NaHCO3 aqueous solution, respectively. All of the sample aqueous solutions were measured at RT.
The fluorescence spectra of the mulberry extracts solution samples were measured by a JASCO FP-6500 fluorescence spectrophotometer at RT. The mulberry extracts powder (1.0 × 10−2 wt%) or the powder (1.0 × 10−2 wt%) and AlCl3 (0.050 M) were dissolved into freshly distilled water to prepare solutions.
As one of the evaluation techniques of the reducibility of mulberry extracts, the free radical scavenging method using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) was adopted. The DPPH method is a common antioxidant assay widely used [
Orange oily material was obtained by the extraction from mulberry branches and trunks with ethanol. The mulberry ethanol-extracts are not soluble in water and were used as ethanol/water mixed solution for the dyeing experiment. The result shows that the colour of wool fabric turns very pale yellow by the treatment with the ethanol-extracts solution. The L* of wool fabric changes from 87.6 to 85.6 by the treatment and those of the a*, b* are from −0.260, 13.1 to −0.480, 15.7, respectively. The changes in the colour values are very little. It can be said that the dyeability of the mulberry ethanol-extracts for wool is low.
On the other hand, brown powders were obtained by the extraction with water. The yield of the dry powder from the branches and trunks is 8.74% in mass. It was found that wool is dyed with the mulberry water-extracts aqueous solution unlike the ethanol-extracts solution. Then, the dyeability of the mulberry extracts for silk, cotton, ramie, nylon, acrylic and polyester fabric in addition to wool was examined. Only the mulberry water-extracts were used in the subsequent studies. The results show that acrylic and polyester are not dyed at all, cotton and ramie are dyed a little (actually almost not), whereas silk and nylon are dyed with the mulberry extracts, as well as wool. The dyeing results are summarised in
Sample | Wool | Silk | Cotton | Ramie | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
initial | treated | initial | treated | initial | treated | initial | treated | |||||
L* | 87.6 | 81.8 | 95.7 | 82.2 | 95.2 | 90.6 | 95.1 | 89.4 | ||||
a* | −0.260 | −1.95 | −0.0926 | 2.41 | 0.00180 | 1.92 | 0.101 | 2.03 | ||||
b* | 13.1 | 27.7 | 2.45 | 25.8 | 2.45 | 8.49 | 2.43 | 9.35 | ||||
C* | 12.5 | 27.8 | 2.45 | 25.9 | 2.45 | 8.71 | 2.43 | 9.57 | ||||
Nylon | Acrylic | Polyester | ||||||||||
initial | treated | initial | treated | initial | treated | |||||||
L* | 95.1 | 86.5 | 93.5 | 93.3 | 95.2 | 95.3 | ||||||
a* | −1.14 | −4.94 | −0.661 | −0.672 | −0.331 | −0.328 | ||||||
b* | 7.75 | 43.3 | 6.52 | 6.89 | 2.45 | 2.52 | ||||||
C* | 7.83 | 43.5 | 6.55 | 6.92 | 2.47 | 2.54 | ||||||
but negative, which means the colours include a green component. The effective dyeing results were obtained for wool, silk and nylon samples and it is concluded that the mulberry extracts dye the three kinds of fibres. The dyeable three fibres have charges and amide bonds in their molecular chains in common. The results show that the dyeabilities are due to such the chemical characteristics and higher ordered structures of the fibres. In fact, the fibres are dyed with acid dyes and their dyeability against a sort of dye molecules is very similar.
The dependence of the dyeability of wool on the mulberry extracts concentration or the dyeing time was also examined [
The colour fastness for the fabrics dyed by the mulberry extracts to washing and light are studied by the authors and will be reported.
It is well known that the colour of natural pigments change with pH [
It is expected that the pH dependence of the obtained colour of the dyed wool may be caused by the change in colour of the extracts in the dyeing solution.
dyed wool. The changed chemical structure of pigments in the dyeing solution according to the pH may be fixed after the treatment. As reported and discussed at §3.4, the mulberry extracts contain flavonoids, which show reducibility. The colour of such the flavonoids changes under basic condition [
It is also generally well known that the dyeing results are significantly influenced by the dyeing temperature [
The change in the resulting colours of dyed fabrics depending upon dyeing temperature was observed. The colours of the three kinds of dyed fabrics become commonly more brownish and darker with an increase in temperature. The deepest colours for dyed wool, silk and nylon are obtained at 90˚C. The obtained colour values are summarised in
cording to the dyeing temperature are shown in
The amount of dyestuffs adsorbed onto fibres, their distribution in fibre materials, the sort and the composition of pigments adsorbed and so on are strongly controlled by dyeing temperature and then the dyeing results (obtained colours) are associated with them. If the mulberry extracts contain pigments, which work as a reductant, the colour of the pigment could be changed by oxidation. The oxidation reaction of the pigments may be promoted by heating. Therefore, there is a possibility that the higher temperature during the dyeing accelerates the oxidation of the pigments of the extracts. However, the change in the colour of the dyeing solution was not observed even at higher temperatures.
Sample | Wool | Silk | Nylon | ||||||
---|---|---|---|---|---|---|---|---|---|
L* | a* | b* | L* | a* | b* | L* | a* | b* | |
Initial | 87.6 | ?0.26 | 13.1 | 95.7 | ?0.09 | 2.45 | 95.1 | ?1.14 | 7.75 |
30˚C | 84.0 | ?2.32 | 24.6 | 86.2 | 1.18 | 21.9 | 92.5 | ?7.09 | 37.7 |
40˚C | 81.8 | ?1.95 | 27.7 | 82.2 | 2.41 | 25.8 | 86.5 | ?4.94 | 43.3 |
50˚C | 80.1 | ?1.14 | 30.8 | 78.3 | 3.64 | 27.5 | 82.8 | ?0.39 | 50.9 |
60˚C | 76.9 | 0.55 | 32.8 | 75.3 | 4.04 | 26.4 | 77.4 | 2.09 | 49.2 |
70˚C | 72.9 | 2.88 | 33.0 | 72.3 | 5.19 | 26.7 | 72.4 | 5.11 | 47.5 |
80˚C | 67.8 | 5.81 | 32.8 | 68.5 | 5.85 | 26.1 | 66.9 | 6.67 | 43.2 |
90˚C | 64.2 | 7.96 | 34.9 | 69.4 | 5.43 | 27.0 | 64.0 | 7.89 | 42.6 |
Morin, isorhamnetin, kaempferol, quercetin and myricetin show fluorescence, when they form a complex with Al3+ [
Then, fluorescence spectra were measured to get information on the optical properties of the mulberry extracts.
tering light from water [
The emission spectra for both of the solution with 310 nm excitation light are almost same. This means that the emission caused with 310 nm excitation light is due to fluorescent substances contained in the extracts themselves and the another emission caused with 410 nm excitation light is due to complexes formed from the extracts and Al3+. The fluorescence for the complexes contributes
the colour shift observed in
The phenolic substances contained in trees belonging to Moraceae family were studied and analyses were made [
It is expected that dyed fabrics with the mulberry extracts and mulberry extracts/AlCl3 show fluorescence. Wool fabric was treated with (1) AlCl3 solution, (2) the mulberry extracts solution or (3) first AlCl3 solution and second the mulberry extracts solution, and the obtained fabric samples were irradiated with 365 nm UV light.
While the wool treated with AlCl3 solution does not show fluorescence (d), mulberry extracts-dyed one (e) and AlCl3/mulberry extracts-dyed one (f) show fluorescence. The fluorescence emission intensity of the AlCl3/mulberry extracts- dyed wool is higher than that of the mulberry extracts-dyed one. The results
show the fabrics treated with the mulberry extracts solution show fluorescence and the fluorescence intensity is increased when the dyeing is combined with
AlCl3 solution and irradiation is made by UV light, of which wavelength is in the vicinity of 410 nm or which includes longer wavelength lights.
The results indicate that the mulberry extracts contain flavonols such as morin and quercetin as described previously.
If they contain such the flavonols, they show reducing property. It is known that the many flavonoids show antioxidant characteristic. Then, the reducibility of mulberry extracts was examined by DPPH method.
The results indicate that flavonoids contained in the extracts may play an important role for the dyeing as dyestuffs. Further analytical study is needed to know the composition of mulberry extracts.
The wool, nylon and silk fabrics are dyed brownish and yellowish colours by the extracts from the mulberry branches and trunks, which are extracted with hot water. The obtained colours depend on the extracts concentration in the dye solution, dyeing time, dye solution pH and dyeing temperature. The mulberry ex-
tracts show fluorescence and reducing property. It is indicated that the mulberry extracts contain flavonols, which form complexes with Al3+. The wool treated with the mulberry extracts or AlCl3/mulberry extracts shows fluorescence and the emission intensity is increased by the combination with AlCl3.
The authors wish to thank sincerely Prof. Ichida of Kyoto Institute of Technology and for his very kind supply of the mulberry branches and trunks and fruitful discussion.
Nguyễn, T.K.T., Kuroda, A., Urakawa, H. and Yasunaga, H. (2017) Dyeing Fabrics by Using Extracts from Mulberry Branch/Trunk 1. Dyeability and Fluorescence Property. American Journal of Plant Sciences, 8, 1888-1903. https://doi.org/10.4236/ajps.2017.88128