1. Introduction
Ultraviolet (UV) radiation exposure can cause skin aging and inflammation due to the damage to collagen, hyaluronic acid, and protein [
1,
2,
3,
4]. Some functional fabrics can protect the skin exposed to UV rays by absorbing, transmitting, and reflecting UV light. For the functionalization of UV protective fabrics, the insertion of colorants onto the fabric surface, viz., dyeing, can manipulate light transmission, thereby resulting in photo stabilizing effects when the dyed fabrics shield UV illumination from 290 to 400 nm wavelength. On the other hand, UV-absorbing or shielding materials such as titanium dioxide and zinc oxide need to be incorporated.
Several researchers have studied how to adsorb zinc oxide (ZnO) nanoparticles onto cotton fabrics. The potential characteristics of ZnO are appropriate for UV protective materials, such as easy processibility, cost accessibility, biocompatibility, great electron mobility with high excitation binding energy, air-thermal stability, intensive photocatalytic ability, corrosion stability, and solar-UV absorption ability [
5,
6,
7,
8,
9]. Belay et al. could increase the UV protection factor (UPF) of cotton fabrics coated with ZnO nanoparticles via in-situ deposition, compared with the precipitation method [
10]. According to Rise et al., the UV absorption wavelength of ZnO stands out at 368 nm, equivalent to the band gap at 3.37 eV [
11]. For optimal UV protection, it is adequate for sun-blocking materials to cover the wide range of UV absorption, including UVA and UVB.
With the aforementioned excellence of ZnO, another UV protective material is also required to strengthen the absorption range of ZnO. Several researchers have recently discovered organic UV absorbers from plant extracts for marine organisms, algae [
12,
13,
14,
15,
16,
17]. Regardless of its non-toxicity, mycosporine and its derivatives are expensive for practical use, compared with phenolic compounds from natural plant extracts. Polyphenols, one of the typical phytochemicals, can provide skin photoprotection [
2,
4]. Tannins of the polyphenols are mostly contained in berries, pomegranates, and green tea leaves [
4,
12]. The tannins from phenolic compounds can also be used as antioxidants. He et al. used polyphenols to scavenge free radicals from the hydroxyl groups of polyphenols, thereby inhibiting the generation of radicals and polymerization of photosensitive ink via the formation of quinones [
18]. However, it is known for polyphenolic compounds to discolor and decolorize its applied fibers and textiles, resulting in poor color fastness to light. Overall, the possibility of discoloration by the polyphenols is controversial; hence, other factors in fadedness should also be considered, such as photodegradation in the manufacturing, storage, and usage processes.
As mentioned above, photodegradation can be classified into both internal material attributes and external environmental factors. Groeneveld et al. sorted the external factors as listed below: light irradiation, oxygen, temperature, and the internal factors: the inherent characteristics of colorants, photocatalysts, and textile substrates [
19]. However, there are different photo mechanisms that excite different chromophores between visible and UV regions. According to Rader and Schmidtke [
20], the concentration of oxygen can be another external factor since the rate of photodegradation can decrease in anaerobic environments because the oxidation causes decolorization by decomposing chromophores. The hydrogen ion exponent (pH) of dyeing solution, one of the internal factors, is a paramount cause of color change through photocatalyst oxidation. Not only the pH dye solution, but the type of textile substrate is also of vital importance. Nylon, wool, silk, and leather can easily be discolored or yellowed due to the chain scission of amino groups after being exposed to UV, nitrogen dioxide, ozone, moisture, and heat. Despite the weakness of proteinaceous fibers to photodegradation, acid dyeing enables wool to prevent discoloration or decolorization by neutralizing negative charges and forming cystine bonds on the woolen surface.
To minimize the decolorization affected by the factors mentioned above, it is necessary to understand photochemical mechanisms, which are dependent on the photon absorption of colorants or dye molecules. According to Michelin and Hoffmann, three photochemical mechanisms can be explained through direct or indirect photochemical reactions by photosensitizers, photocatalysts, and hydrogen, as follows: photoisomerization, photooxidation, and photoreduction [
21]. Photoisomerization arises from the structural transformation of photocatalytic chromophores, for instance, chlorophylls glowing with autumn color into red, yellow, or brown. According to Abiola et al. (2020), trans-isomers of chromophores in natural dyes can be converted to
cis-isomers when absorbing light irradiation of a short wavelength, resulting in discoloration of the dyed textiles [
22]. Naphthoquinone, one of the quinonoid compounds, comprises many isomers, such as alkannin, lawsone, juglone, lapachol, plumbargin, and shikonin [
23,
24]. La and Giusti investigated the photochromism of delphinidins in anthocyanin dyes between
trans- and cis-acylated isomers that were induced by visible UV light reversibly [
25]. Carotenoids, one of the photoprotective dyes, are generated by the
cis-trans isomerization of polar lutein and zeaxanthin, whereas the carotenoids turn into xanthophylls or
β-cryptoxanthins due to the oxidation of the 3-hydroxy-
β-end group of the xanthophyll [
26]. The chromatic structures of chromophore groups can also be transformed by benzoyl peroxide, which causes the discoloration of their applied textiles. According to Rafiq et al., photooxidation occurs when photocatalytic dyes produce holes and electrons in excited states where photon absorption is higher than each bandgap energy of the photocatalytic dyes [
27]. The chromophoric group photooxidates polyolefins by the generation of reactive oxygen species and hydrogen peroxide, then breaks down into hydroxyl and alkoxy radicals under Norrish and cage reactions, and finally terminates recombination in stabilized states [
28]. On the other hand, photoreduction occurs when excited electrons, such as ketones, react with hydrogen from other molecular materials. The difference between photooxidation and photoreduction is the area of decolorization; for example, the only faded area of photo reduced fabrics is where they were exposed to light, whereas the area covered with wrinkles on other screens did not fade. In conclusion, discoloration can be prevented by dyeing fabrics with photo-protective colorants with monochromaticity, by coordinating with metallic compounds, and by treating antioxidants and UV absorbers or blockers.
To avoid photodegradation, metal-polyphenolic chelating compounds can benefit from both metal cations donating electrons, hydrogen, and tannin against photooxidation. Catechol or gallol groups in the polyphenols play a role as ligands to chelate with metals, metal oxides, or carbon nanomaterials [
13,
14]. Feng et al. state that catechol's exceptional capacity to adsorb, attach, and bind to a variety of substrates, from hydrophilic to hydrophobic or from organic to inorganic surfaces, allows it to coordinate with metals such as Fe, Cu, Zn, and Al [
14]. Wang et al. demonstrated that electroless deposition of ZnO and cotton surface modification could maintain high UPF mechanical properties even after 50 launderings with palladium as a catalyst and tannic acid as a linking agent [
29]. The improvement in UV protection could be attributed to the fact that a large amount of ZnO and polyphenols from plant extracts were adsorbed onto inherently hollow cotton fibers, leading to UV absorption. The metal-polyphenolic coordination materials can result in synergistic effects on antioxidants and antiaging against the broad ranges of UV light, with tannins acting as organic UV absorbers and ZnO acting as inorganic UV blockers [
3].
The purpose of this work was to functionalize UV-protective textiles using metallic mordanting, UV absorptive treatment, and natural coloring. Regarding the violet and yellow dyeing of cotton and polyester, two chromophores of naphthoquinone and β-carotenoid were extracted from plant roots and seeds, and FTIR investigations were then performed to identify the functional groups and dye constituents. To improve UV light absorption, zinc oxide and polyphenols were treated on the dyed fabrics. The reflectance analyses were demonstrated to prove the effectiveness of ZnO/polyphenol treatment by comparing the color differences (ΔE) between untreated and treated fabrics after UV exposure. Additionally, the color variation of four different metallic mordant types—particularly Cu-post mordanting—was examined using colorimetric metrics on the dyed materials, such as hue angle, chroma, a*, b*, and color depth (K/S).
2. Materials and Methods
2.1. Materials
In this study, violet and yellow in complementary colors were chosen to find the effects of mordanting, UV protective treatment, and exposure to UVC rays on the chromatic variation of dyed fabrics. As natural dyes, this work selected Gromwell roots (GWR) or Lithospermum erythrorhizon pellets (originated from China) and Cape jasmine seeds (CJS) or Gardenia jasminoides (originated from Korea). Both dyes were purchased at the Boncho Myeong-ga Industry-Daejeon University Cooperation Foundation. The extraction of GWR-Violet and CJS-Yellow dyes was conducted using anhydrous ethanol (purity 99%, Shicorp., Korea) and tertiary purified water (Joylife Corp., Korea), respectively. To facilitate the extraction of GWR-Violet dyes, 99% acetic acid (Samyang Ltd., Korea) was diluted. Zinc oxide (ZnO) and tannin as polyphenolic compounds, which derived from gallnut (Quercus infectoria) were selected to increase UV absorption in this research. The zinc oxide powder was obtained from Gooworl Corp., and the gallnut powder from Yongcheon Herb Medicine Farming Association Co., Ltd. (originated from China). The ZnO particles was dispersed in tertiary purified water and dimethyl sulfoxide (DMSO) (purity 99.8%, KisanBio, Korea).
To investigate the influence of post-mordanting on color variation, four mordants were used: aluminum potassium sulfate (KAl(SO4)2), copper acetate (Cu(OAc)2), tin chloride (SnCl2), and iron sulfate (FeSO4). The aluminum potassium sulfate and iron sulfate were supplied from Sinsegi Science Corp. (Korea). Common copper plates were dissolved in diluted acetic acid (5 M) to make a copper acetate solution. A tin chloride solution was prepared by dissolving tin powder (96.5% Sn, 500 mesh) in 36.5% hydrochloric acid (Junsei Chemical Ltd., Japen). The tin powder was obtained from Juju Industry (Korea), whose size ranged from 25 µm to 80 µm.
2.2. Extraction of Natural Dyes and Preparation of Mordants
The first step was to extract the violet dyes from Gromwell roots (GWR), as shown in
Figure 1 (a). 60 g of GWR pellets were mixed with 500 mL of ethanol. After diluting 50 mL of 5M acetic acid with tertiary filtered water, it was added to the GWR/ethanol solution. The solution was kept at room temperature for 72 hours with the container lid closed to prevent ethanol from evaporating. For the extraction of yellow dyes, 50 g of dried Cape Jasmine seeds (CJS), as seen in
Figure 1(b), were soaked in 500 mL of water at 40 °C for 24 hours. After 24 hours, the first CJS-Yellow extract was filtered through a piece of muslin cloth into an Erlenmeyer flask, then left with its neck wrapped in aluminum foil. The residue seeds were extracted in another 500 mL of water in the second round, followed by the same procedure as above. After another 24 hours, the second CJS extract was added to the first dye solution for homogenization.
As shown in
Figure 1(c-d), the second step was to prepare the photo-absorbers, zinc oxide powder, and crushed gallnut for UV protective treatment. The ZnO (6% o.w.f.) was dispersed in a 500 mL mixture of 350 mL of ethanol and 150 mL of purified water for the first treatment. For the second treatment, another 12% o.w.f. of ZnO powder was in 50 mL of DMSO. Both ZnO dispersed solutions were magnetically stirred for 60 mins, followed by ultrasonication for five mins. To extract pyrogallol acid from polyphenolic tannin, 25 g of gallnut was ground in a mortar with a pestle, and the residual dust was removed. 125 mL of purified water was poured into the ground gallnut, then boiled for one hour. After extracting the boiled solution, another 125 mL of water was added to the filtered gallnut, which was then boiled for another hour. Finally, all of the extracts were gathered into one container.
The next step was to dissolve metallic salts and thin metal pellets in each solvent for pre- and post-mordanting. The aluminum potassium sulfate (8% o.w.f.) and iron sulfate (2% o.w.f.) powders in
Figure 1(e, h) were respectively stirred in distilled water of each 1 L for 60 mins and kept at room temperature to stabilize for another 60 mins. The copper plates were sliced into pieces ranging in size from 3 mm to 5 mm (
Figure 1(f)). Then, 10 g of copper pellets were dissolved in a solution of 25 mL of purified water and 25 g of 5 M acetic acid. To accelerate the dissolving reaction, 9.7 M hydroperoxide was carefully added dropwise to the copper acetate solution and left at room temperature for 48 hours. The copper acetate solution turned blue, and the residual Cu pieces were filtered from the blue solution. For the preparation of tin chloride mordants, 2.457 g of tin power (500 mesh) was dissolved in 10 mL of 37% HCl in a three-neck reaction flask with rubber septa sealing and a magnet stirred at 75 °C. After 2 hours, 2 mL of purified water was added to the solution, then left on the hot plate without stirring for 12 hours. Finally, the tin chloride solution was cooled to room temperature for another 12 hours.
2.3. Natural Dyeing and Mordanting
In this study, two sets of cotton and polyester fabrics were dyed. Polyester nanofilament and organic cotton yarns were supplied by Kolon Fashion Material Ltd. and Hanjoong Union Ltd., respectively. Combed cotton for warp yarns was provided from Dong-A TOL Ltd., where weaving sampling was processed in this work.
As listed in
Table 1, the first set for violet-dyeing were two types of twill-woven fabrics, made of (a) 100% cotton combed yarn (84.7 Nm) for both warp and weft and (b) the same cotton yarn for warp/polyester nanofilaments (8.33 tex) for weft. The second set for yellow-dyeing also included two types of satin-woven fabrics, comprising (c) 100% organic cotton (101.6 Nm) for weft with 100% cotton combed yarn (84.7 Nm) for warp and (d) the same cotton warp with polyester (8.33 tex). Each density (warp/weft) was as follows: (a) 172.5/110.4, (b) 104.0/104.0, (c) 145.7/122.8, and (d) 145.7/122.4 (unit: thds/inch). All fabrics were cut to 10 cm by 10 cm in size. Prior to dying, the cut fabrics were refined in tertiary purified water. After that, those were squeezed and dried at room temperature. For pre-mordanting, the fabrics were immersed in a KAl(SO
4)
2 solution for 20 minutes.
For dyeing in violet, first of all, 2 L of preheated water at 40 °C was poured into 100 mL of the Gromwell root extract. After being pre-mordanted, 15 g of wet twill fabrics were soaked in the extract. To prevent dye aggregation and bubble formation, the fabrics were turned over front and back and kept without floating. After 40 minutes, the violet-dyed fabrics were taken out of the extract, soaked in clean water for 10 minutes, and rinsed in flowing water. Finally, those were squeezed, dried in an oven at 35 °C, and ironed for wrinkle removal. This process is one cycle of violet dyeing. Before the second cycle, the dried fabrics were Al-mordanted repeatedly to strengthen color depth. As for yellow-dyeing, 27 g of wet satin fabrics were prepared as above. The fabrics were immersed in the Cape Jasmine extract in a bath ratio of 1:20 at 70 °C for 30 minutes. The other processes underwent the same process as violet dyeing.
The first UV protective treatment began between the third and fourth dyeing cycles. First, the dyed fabrics were immersed in the dispersion of ZnO in ethanol or water for 30 minutes, rinsed, squeezed, dried, and ironed, as aforementioned. For the second UV treatment, the four-time-dyed fabrics were soaked in the dispersion of ZnO in DMSO for 20 minutes, and the other procedure was identical to the previous one. As for the polyphenol treatment, half pieces of the ZnO-treated fabrics were put in the gallnut extract at 40 °C, then heated to 70 °C for 30 minutes. The ZnO and phenol were treated twice, respectively.
Post-mordanting started after the fifth dyeing cycle, except Al- pre-mordanting. First, 50 mL of copper acetate was poured into 1 L of purified water, and one fourth of the of the dyed fabrics were sunk into the diluted solution for 10 minutes. The Cu-mordanted fabrics were squeezed, soaked, rinsed in water, dried, and ironed. Then, Cu-post-mordanting was repeated for another 10 minutes. As for Sn-post-mordanting, 25 mL of tin chloride was diluted in 500 mL of distilled water. The other steps were the same as those of Cu-mordanting. The procedure for Fe-mordanting with iron sulfate powder was the same as above.
2.4. Exposure to UV-C and D65 Lamps
To evaluate the fadedness of dyed fabrics by UV or artificial lamps, a new design of UV testing apparatus was invented under the modification of ISO 105-B02:2014 Textiles in this research. In
Figure 2, the apparatus consisted of illuminating sources, a rotating cylinder holding samples, a motor and its controller, and a chamber to block UV-C light.
Figure 2(a) shows the open tetradecagonal cylinder of 17 cm in diameter with 14 pieces (w: 7 cm x h: 15 cm) to hold testing fabrics. The samples were cut at 2 cm x 5 cm. A couple of sample pieces were held inside with clips and tapes, as shown in
Figure 2(b). A Xenon lamp was replaced with a 6500K LED lamp (60 Hz, 40W, Yuzhong Gaohong Ltd., China) and two UV-C lamps (8W, Osram, Italy, Phillips, Poland). The UV lamps were stuck with their backs to each other and hung on the chamber ceiling. The brushless DC motor (K8XH50N2, GGM, Korea) was rotating at a rate of 10.5 rpm during the testing (
Figure 2(c)). The motor was connected to the PLC controller and touch screen, as seen in
Figure 2(d). The testing samples were exposed to UV lamps twice per 10 hours and the D65 light for 20 hours. Total exposure time was 40 hours under the data-logged chamber condition at 30.3 °C and 27.8% RH average.
2.5. Characterization and Chromatic Analyses
To investigate the components and functional groups of the natural dyes, attenuated Fourier transform infrared (ATR-FTIR) spectrometry (Invenio-R, Bruker, USA) was used. The FTIR measurement ranged from 400 cm-1 to 4000 cm-1, at a resolution of 4.0. The spectral analyses were conducted using KnowItAll Informatic System 2024 (Wiley Science Solutions) and the OPUS (Bruker Optik GmbH) program.
To confirm the ZnO crystalline structure and the size of ZnO particles, the D/Max-2200/VPC (Rigaku, Japan) X-ray diffractometer (XRD) was employed. The measurement parameters of X-ray diffraction were set at 40 kV/30 mA with a scanning range of 2θ from 25° to 85°. The XRD peaks were analyzed with reference cards from the Joint Committee on Powder Diffraction Standards (JCPDS) database, and the ZnO size was estimated through the Debey-Scherrer equation using Origin Pro 2024 software (OriginLab, USA). The average ZnO particle size was calculated in the Debey-Scherrer equation [
30]. The crystallite size
was estimated from Eq. (1):
where κ, λ, β, θ are Scherrer’ constant (normally considered as 0.9), wavelength of the x-ray beam (copper used in this study, λ 1.54184 Å), the full width at half maximum (FWHM) of the peak, and Bragg’s angle, respectively.
To find the effects of various mordants and UV exposure on the color and UV absorbance of the dyed fabrics, the UV-3600i Plus (Shimadzu, Japan) was utilized to measure UV-vis-NIR spectra with its deuterium lamp and integrating sphere attachment. The reflectance in the UV-vis spectrum was measured at an interval of 2 nm, and the light source was automatically switched at 310 nm. The reflectance (R) was converted into color strength (K/S value) at 600 nm (λ
max GWR-V) and at 450 nm (λ
max CHS-Y) through Kubelka-Munk equation Eq. (2), as follows:
From the UV-vis spectra, the chromaticity and color difference coordination were obtained under a standard observer at 10° via the OriginPro 2024 program. The reflectance spectrum was converted to colorimetric parameters L, a*, b* in CIELAB with color space (u’, v’) coordinates. The total color difference (ΔE) between a testing sample and a reference sample was summarized by Eq. (3) as follows:
where L, a*, b* values indicate the color differences in lightness (L), the amount of red/magenta (+) from green (-), and the amount of yellow (+) from blue (-) between reference and test samples. The values of chroma (C), and hue angle (H) were estimated by the following Eq.(4-5):
Based on the colorimetric parameters above, this study adopted the CIEDE 2000 and CMC formulae defined by the Color Measurement Committee of the Society of Dyers and Colorists for the optimum values of color difference. The weighing factors were set as follows: kL = 1.5, kC = 1.9, and CMC = 2:1 [
31,
32]. The values were converted through the ColoCalculator programs, which are provided by Lindbloom and Osram Inc. (MA, USA).
5. Conclusions
In this work, the UV protective fabrics were prepared through natural dyeing with shikonin and xanthophyll colorants, ZnO/polyphenol treatment, and Cu-post-mordanting. The chromaticity of violet or yellow dyed fabrics was analyzed via UV-vis spectroscope with CIE colorimetric parameters of K/S, lightness, chroma, hue, a*, b*, and ΔE. As the results, the shikonin, in the combination with polyphenol caused the dyed cotton or polyester to vary extensively in chromaticity from violet to purple and brown to beige, with the highest K/S and the widespread variation. The violet dyeing led to the increase in the ΔE, and b* values, yet a decrease in the K/S, a*, chroma and hue angle. In contrast, the non-photochemical chromophores of xanthophyll contributed to the relatively coherent hue, chroma, and lightness in yellow compared with the violet dye fabrics. The ZnO treatment increased the reflectance rate in UVA-UVB ranges in UV-vis spectra, whereas the ZnO/polyphenol treatment could contribute to UV absorption, owing to tannin from gallnut. The Cu-mordants helped enhance the fixation of colorants, consequently minimizing the ΔE between non-exposed and UV-exposed samples. In this study, it was concluded that the combination of xanthophyll colorant, ZnO/polyphenol absorber, and Cu mordant was an effective strategy to shield UV light and protect skin.
Figure 1.
Photographs of (a) Gromwell root dyes, (b) Cape Jasmine seed dyes, (c) zinc oxide (ZnO), (d) gallnut, (e) aluminum potassium sulfate powder, (f) copper pieces for copper acetate solution, (g) tin powder for tin chloride solution, and (h) iron sulfate powder.
Figure 1.
Photographs of (a) Gromwell root dyes, (b) Cape Jasmine seed dyes, (c) zinc oxide (ZnO), (d) gallnut, (e) aluminum potassium sulfate powder, (f) copper pieces for copper acetate solution, (g) tin powder for tin chloride solution, and (h) iron sulfate powder.
Figure 2.
Photographs of UV light exposure apparatus: (a) a tetradecagonal holder; (b) a rotating apparatus with a 6500K lamp; (c) a rotating DC motor with UV-C lamps; and (d) a PLC controller with a touch screen in the chamber.
Figure 2.
Photographs of UV light exposure apparatus: (a) a tetradecagonal holder; (b) a rotating apparatus with a 6500K lamp; (c) a rotating DC motor with UV-C lamps; and (d) a PLC controller with a touch screen in the chamber.
Figure 3.
(a) Attenuated FTIR spectra of Gromwell roots-violet dyes, Cape Jasmine seeds-yellow dyes, and (b) XRD peaks of ZnO nanoparticles.
Figure 3.
(a) Attenuated FTIR spectra of Gromwell roots-violet dyes, Cape Jasmine seeds-yellow dyes, and (b) XRD peaks of ZnO nanoparticles.
Figure 4.
CIE diagrams of (a) cotton and (b) polyester fabrics dyed with shikonin and xanthophyll.
Figure 4.
CIE diagrams of (a) cotton and (b) polyester fabrics dyed with shikonin and xanthophyll.
Figure 5.
Reflective spectra of the cotton, polyester fabrics dyed with (a) shikonin and (b) xanthophyll with/without UV protective treatment.
Figure 5.
Reflective spectra of the cotton, polyester fabrics dyed with (a) shikonin and (b) xanthophyll with/without UV protective treatment.
Figure 6.
Colorimetric parameters of (a) K/S and (b) b* values of natural dyed cotton and polyester.
Figure 6.
Colorimetric parameters of (a) K/S and (b) b* values of natural dyed cotton and polyester.
Figure 7.
Comparison of (a) K/S and (b) b* values of the dyed fabrics without/with ZnO/polyphenol treatment between unexposed and exposed to UV light.
Figure 7.
Comparison of (a) K/S and (b) b* values of the dyed fabrics without/with ZnO/polyphenol treatment between unexposed and exposed to UV light.
Figure 8.
Reflectance curves of the violet-dyed (a) cotton, (b) polyester, and the yellow-dyed (c) cotton, and (d) polyester without/with Cu-mordanted before/after UV light exposure in the UVA and UVB ranges.
Figure 8.
Reflectance curves of the violet-dyed (a) cotton, (b) polyester, and the yellow-dyed (c) cotton, and (d) polyester without/with Cu-mordanted before/after UV light exposure in the UVA and UVB ranges.
Figure 9.
Comparison of (a) chroma and (b) hue angle values between Cu-mordanted cotton and polyester before and after UV exposure.
Figure 9.
Comparison of (a) chroma and (b) hue angle values between Cu-mordanted cotton and polyester before and after UV exposure.
Table 3.
Color difference of the violet, yellow dyed fabrics before and after exposure to UV light.
Table 3.
Color difference of the violet, yellow dyed fabrics before and after exposure to UV light.
Sample |
CIE1976 ΔEab
|
CMC ΔEcmc (2:1) |
CIEDE2000 ΔE00
|
Mean ΔE±Std. |
11C, 11C_0 |
37.03 |
27.51 |
25.00 |
29.85±6.35 |
21C, 21C_0 |
32.64 |
26.15 |
21.46 |
26.75±5.61 |
31C, 31C_0 |
6.60 |
8.70 |
22.57 |
12.62±8.68 |
12P, 12P_0 |
24.82 |
18.65 |
21.59 |
21.69±3.09 |
22P, 22P_0 |
22.26 |
18.26 |
21.61 |
20.71±2.15 |
32P, 32P_0 |
6.22 |
7.92 |
18.65 |
10.93±6.74 |
41C, 41C_0 |
7.49 |
3.35 |
18.01 |
9.62±7.56 |
51C, 51C_0 |
7.98 |
3.74 |
4.79 |
5.50±2.21 |
61C, 61C_0 |
2.60 |
1.13 |
5.95 |
3.23±2.47 |
42P, 42P_0 |
8.16 |
3.63 |
18.66 |
10.15±7.71 |
52P, 52P_0 |
4.46 |
2.22 |
2.90 |
3.19±1.15 |
62P, 62P_0 |
1.60 |
1.06 |
2.44 |
1.70±0.70 |
Table 4.
Reflectance rates of the dyed cotton and polyester samples in UV-B (at 294 nm).
Table 4.
Reflectance rates of the dyed cotton and polyester samples in UV-B (at 294 nm).
Violet-Dyed Sample |
Reflectance (%) |
Yellow-Dyed Sample |
Reflectance (%) |
11C |
11.14 |
41C |
8.81 |
21C |
13.60 |
51C |
10.94 |
31C |
3.84 |
61C |
3.70 |
12P |
5.57 |
42P |
7.43 |
22P |
13.01 |
52P |
7.57 |
32P |
5.28 |
62P |
3.69 |
Table 5.
Comparisons in color differences (ΔE) between the unexposed and UV-exposed samples of Cu-mordanting with or without zinc oxide and polyphenol treatments.
Table 5.
Comparisons in color differences (ΔE) between the unexposed and UV-exposed samples of Cu-mordanting with or without zinc oxide and polyphenol treatments.
Sample |
CIE1976 ΔEab
|
CMC ΔEcmc (2:1)
|
CIEDE2000 ΔE00
|
Mean ΔE±Std. |
15C, 15C_0 |
30.27 |
25.83 |
21.59 |
25.90±4.34 |
15P, 15P_0 |
17.58 |
17.63 |
12.89 |
16.03 ± 2.72 |
35C, 35C_0 |
6.15 |
2.77 |
2.90 |
4.42±1.64 |
35P, 35P_0 |
4.55 |
2.26 |
3.13 |
4.43±1.24 |
45C, 45C_0 |
6.74 |
2.05 |
1.98 |
3.94±2.49 |
45P, 45P_0 |
4.45 |
1.07 |
1.12 |
2.58±1.70 |
65C, 65C_0 |
3.28 |
1.43 |
1.57 |
2.09±1.03 |
65P, 65P_0 |
1.00 |
0.65 |
0.41 |
0.69±0.30 |