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Ozone treatment of Angora rabbit fiber
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Journal of Cleaner Production 16 (2008) 1900e1906 www.elsevier.com/locate/jclepro
Ozone treatment of Angora rabbit fiber _ Bahtiyari b, A.E. Ko¨rlu¨ b,*, K. Duran b S. Perincek a, M.I. b
a _ Emel Akın Vacational High School, Izmir, Turkey _ Department of Textile Engineering, Ege University, Ege University Campus, Bornova, Izmir 35100, Turkey
Received 20 October 2007; received in revised form 31 December 2007; accepted 15 January 2008 Available online 10 March 2008
Abstract The aim of this study was to investigate a novel bleaching technique for Angora rabbit fiber. For this purpose, a detailed investigation on the role of the fiber moisture, pH, and treatment time during ozonation was carried out. Also, the effect of ozonation on the dyeing properties of Angora rabbit fibers was researched. Consequently, it was found that ozonation improved the degree of whiteness and dyeability of Angora rabbit fiber. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Ozone; Angora rabbit fiber; Oxidative bleaching; Finishing; Dyeing; FT-IR; SEM
1. Introduction Angora is a keratinous textile material, produced by the long-haired Angora rabbit [1]. The Angora rabbit (Oryctolagus cuniculus) is a very old breed of rabbit and a species of the order Lagomorpha, believed to have originated from Ankara, Turkey [1e5]. The Romans bred Angora rabbits and the modern Angora rabbit industry dates from the 1700s. Until 1965, France was the leading producer; the world market is now dominated by fiber produced in China. The other producers are France, Chile, Argentina, Hungary, Germany, Finland, and India [2,6]. Production of the Angora fiber is the result of a pair of autosomal and recessive genes that cause an extension of the active phase in the hair follicle from the normal 5e7 weeks in fur rabbits to 12e16 weeks in Angora rabbits [2]. White Angora has been favored in selection because of the associated ease of dyeing. However, the move towards naturally colored fiber is evident in Angora as in other fiber markets [7]. There are different Angora rabbit breeds according to which the colors can change from white to black (blue, chocolate, fawn, tortoise, chinchilla, sable, and chestnut) [8]. * Corresponding author. Tel./fax: þ90 232 339 92 22. E-mail address: [email protected] (A.E. Ko¨rlu¨). 0959-6526/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2008.01.005
Angora fiber can be used in several ways. Knitted product is the common fabric type produced, as the bristle content of most Angora fleeces makes it unsuitable for the production of next-to-skin wear or high quality suiting material. The warm nature of Angora fabrics makes it suitable for use in health products for the benefit of arthritis patients and for thermal underwear in cold climates. Angora fiber is usually blended with another fiber such as wool to improve its performance, both in processing and fabric wearability [2]. Rabbit hair is obtained from the pelts of the Angora rabbit. The hair is shorn from the pelts and separated by blowing [9]. This fiber is one of the ‘‘luxury fine fibers,’’ which also include mohair, cashmere, and alpaca. These luxury wools only represent 3% of the world’s clean wool production, but their price can be 10e30 times more than that of sheep wool. Several factors contribute to this difference, including their toughness, lightness, fineness, softness, and their image and reputation [2,6]. Angora fiber has the chemical structure of protein. It consists of spindle-shaped cortical cells [10]. Angora is a medullated fiber, which makes it lightweight and slick. It is as fine as the best cashmere, that is, about 14e16 mm. Angora is a heterotypic fleece. It contains 1% coarse hair called bristles. However, unlike other textile fleeces (especially mohair), bristles are considered desirable, as they prevent felting and impart the characteristic fluffiness [2,6,10,11]. Angora fiber
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906
has a low density of about 1.15e1.18 g/cm3, compared to 1.33 g/cm3 for wool and 1.50 g/cm3 for cotton. This makes the Angora garments very light, but warm [2,10]. However, the smooth surface and low inter-fiber friction leads to shedding. Because of smoothness (low friction coefficient), weaving with pure Angora wool becomes difficult [9,10]. The fibers themselves are very clean, as the rabbits produce only 2% of their fiber weight in skin excretions, and also because rabbits clean their own fur. Hence, Angora rabbit fibers do not need scouring. However, in some cases bleaching processes can be carried out. The main bleaching agents for wool are oxidizing and reducing agents, which can also be used for Angora rabbit fibers. However, during the processes like washing, bleaching, and dyeing, these fibers must be processed cautiously because, in the lengthwise view of Angora fibers, the most important issue that attracts attention is the ladder or the beadlike structure of the medulla. For this reason, Angora wool can be treated at a temperature of 70 C to protect the fibers [12e16]. On the other hand, legal restrictions and the national and the international awareness of ecology and pollution control allow new advanced techniques (advanced oxidation processes) and technologies to be used. Therefore, the ozonation process, which requires low temperature [17e19], was investigated in this study in terms of the Angora fiber’s bleaching efficiency and dyeability properties. 2. Experiment Angora rabbit fiber (fineness ¼ 16.26 mm) was used in these experiments. The whiteness degree according to the Stensby formula for raw Angora rabbit fiber is 49.2. In this study, the effect of the rinsing process that was performed after ozonation, the fiber’s water pickup value (WPV) (Eq. (1)), pH, the effect of ozonation time on the whiteness degree was investigated. The effect of the ozonation process on the dyeability of the Angora fiber was researched. The WPV of fibers, which were conditioned at 65% moisture and 20 C, was adjusted to the required value and then ozonated at 25 C for the required time.
Moreover, the effect of the fiber’s WPV at different treatment times was also researched. The WPV was set at 0, 20, 40, 60, 80, and 100%. Also, the ozonation time was set at 5, 10, 15, 30, and 45 min. During these experiments, the ambient temperature and the fiber’s pH were adjusted to 23e25 C and 7, respectively. After the optimization of WPV, the effect of pH (2e3, 7, and 10e11) was studied with fiber at 60% WPV. After all the treatments, the samples were rinsed with water at 50 C for 5 min without the use of any chemicals. At the same time, soft mill water (permuted water) was used in all the experiments. On the other hand, conventional hydrogen peroxide bleaching was carried out in accordance with the recipes in Table 1. Finally, ozonated Angora fibers were dyed with a Milling dyestuff Supranol Fastcyanin GR (C.I. Acid Blue 120) according to Fig. 1 for investigating the effect of ozonation on the dyeing properties of the Angora fiber. As shown in Fig. 1, the material was soaked in the solution at 40 C for 10 min, and then the temperature was raised to 70 C in 30 min. At this temperature, the fibers were treated for 30 min. Then, the dye bath was cooled and the Angora fibers were removed. Then the dyed samples were rinsed in cold (50 ), hot (100 at 50 C), and cold (100 ) water, respectively, and dried at an ambient temperature. The equipment used for ozone bleaching has three components: the ozone generator, the applicator, and the ozone destroyer. The system is fully closed because of the harmful effects of ozone on health. The capacity of the ozone generator (Lundell Aquametrics, Inc.) is 0e5 L/min. Oxygen is supplied to the generator from an oxygen tube and the generator supplies the required ozoneeoxygen mixture to the applicator. The applicator is a cylindrical glass tube with a diffuser at the bottom. In these experiments, the flow rate of the ozone was 1.5 L/min. The Angora samples were placed in the applicator for the required time. To evaluate the results obtained, whiteness change (%), color yields (K/S ), and the damage to the fibers were determined. The whiteness degrees of the samples were examined with a Minolta 3600d spectrophotometer according to the
Weight of impregnated fabric Weight of greige fabric W:P:V: % ¼ 100 Weight of greige fabric
Experiments were carried out in two stages. In the first stage, for investigating the effects of rinsing on the whiteness degree, the Angora fiber with 60% WPV was ozonated for 45 min and the whiteness degree was evaluated before rinsing. Then, the Angora sample was separated into two portions. One of them was rinsed with water at 50 C for 5 min and then set aside for 2 weeks. The other one was set aside for 2 weeks without rinsing. Afterwards, the whiteness degree of the samples set aside were measured and compared.
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ð1Þ
Table 1 Hydrogen peroxide bleaching Sodium pyrophosphate NH3 Gisapol ECO 160 H2O2 (35%) Cottozon 98106 L.R. (1:20)
2.0 g/l pH 9e9.5 2.0 g/l 20.0 ml/l 2.0 ml/l 55 C, 90 min
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906
1902
Fig. 1. Dyeing of Angora rabbit fiber.
Stensby formula and then the changes in whiteness (Eqs. (2) and (3)) were evaluated. Whiteness ðStensbyÞ ¼ L þ 3a 3b
ð2Þ
Whiteness changeðWC Þ ¼ WAfter treatment Þ WBefore treatment 100= WBefore treatment ð3Þ Also, for evaluating the effects of ozonation on the dyeing properties of Angora fibers, CIELab L*, a*, and b* values of samples were measured with Minolta 3600d spectrophotometer (D 65/10 ) and color yields (K/S ) of dyed samples were calculated using the Kubelka Munk equation. Microscopic and solubility tests were performed for investigating the damage to the Angora fiber due to ozonation. Damage to the outer layers (epicuticle) may be revealed by means of the AllwTrden reaction. When fibers are immersed in chlorine or bromine water, bubbles or blisters known as AllwTrden sacs are formed on the surface. Damage to the fiber surface may show up by lessening the size of, or eliminating altogether, the blisters [20]. Alkali solubility values were determined by the ASTM D1283 standard test method. It was calculated as a percentage of the original mass, according to Eq. (4) given here: Alkali solubility% ¼ ðM1 M2 Þ=M1 100
ð4Þ
where M1 e mass of oven-dry samples before sodium hydroxide treatment, and M2 e mass of oven-dry samples after sodium hydroxide treatment. Furthermore, Fourier transform infrared spectroscopy (FTIR) of the Angora fiber was carried out with a Perkin Elmer Spectrum 100. 3. Results and discussion
[17,18,22]. Hence, the effects of rinsing on the whiteness degree were investigated. To establish the results, the whiteness degrees of the rinsed and the unrinsed ozonated Angora samples were measured after 2 weeks. It was found that the Angora rabbit fiber ozonated and rinsed afterward showed a loss of 8.9% in the degree of whiteness while the loss was 25.6% for the unrinsed samples. Finally, it can be said that if the rinsing process was not carried out after ozonation, the whiteness degree of Angora rabbit fiber decreased drastically everyday. Finally, after all the treatments the fibers were rinsed with water at 50 C for 5 min.
3.1.2. Effect of fiber’s WPV and treatment time on whiteness degree of Angora rabbit fiber Today, it is well known from literature and research that the water content of the material is of great importance in terms of the ozonation efficiency [17,18,22,23]. That is why fibers were impregnated with six different water pickup values (0, 20, 40, 60, 80, and 100%) at this stage of the experiments. For investigating the water content’s effects on ozonation efficiency of Angora rabbit fiber, treatment time and the WPV were set to 45 min and 7, respectively. It can be seen from Fig. 2 that the whiteness degree of Angora rabbit fiber after ozonation increased with the rise in the WPV of fibers until a critical pickup value. An interesting point is that the increase in the whiteness degree was the highest when the WPV was about 60%. The 18% increase in whiteness after ozonation for 45 min of the fibers at 60% WPV could not be reached by the fibers with other pickup values. After this critical value, the increase in the WPV of fibers caused a gradual decrease in the whiteness degree. It was found thus that the WPV of fibers had an important effect on the whiteness degree. It is considered that the positive effect of water content of Angora fibers on the whiteness degree is the penetration of ozone gas into the fiber [17,18]. The increase in the water content up to 60% provides penetration of ozone gas into the fiber readily. But after this value of water content, the decomposition of ozone in water gathers speed and the whiteness degree starts to reduce. Hence, it is recommended to ozonate fibers in 60% WPV for optimum effect. After the optimization of Angora rabbit fiber’s WPV, the role of treatment time and pH during ozone bleaching of Angora rabbit fibers were studied (Figs. 3 and 4). All experiments were realized at 45 min and 60% pickup of water.
3.1. Optimization of ozonation treatment 3.1.1. Effect of rinsing process on whiteness degree of ozonated Angora rabbit fiber The removal of soil from the surface of the fabric by the washing process is of prime importance for the efficiency of subsequent processes [21]. Hence, large-scale finishing processes were conducted with rinsing to remove unfixed dye or by-products from the fabric’s surface. In some researches and literature, it was highlighted that during the rinsing process, the by-products that are responsible for the re-yellowing of textile materials after ozonation migrates to the rinsing bath
Fig. 2. Effect of Angora rabbit fibre’s WPV on whiteness degree.
Whiteness Change (%)
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906 20 15 10 5 0 5 min.
10 min.
15 min.
30 min.
45 min.
Fig. 3. Effect of treatment time on whiteness degree.
It is essential to identify the treatment time for the desired bleaching effect of ozonation like other finishing processes. To investigate the effects of ozonation time on the degree of whiteness of the Angora rabbit fiber, it was decided to ozonate the Angora fibers for 5, 10, 15, 30, and 45 min. During ozonation, all samples were at 60% WPV. It was realized that the whiteness degree of Angora rabbit fiber increased with increase in ozonation time. 3.1.3. Effect of empregnated water’s pH on whiteness degree of Angora rabbit fiber The other parameter that affects the ozonation efficiency is the pH of the water that is used in impregnation of Angora rabbit fiber (Fig. 4). Three different pH values (pH 2e3 with buffer acid, 7 with distillated water, 10e11 with caustic soda) were studied in the experiments. During the experiments the tested fiber’s pH was 7.2. According to the results, the ozonation efficiency was restricted in the basic pH values when compared to acidic and neutral pH. Consequently, the lowest whiteness degree was obtained from Angora rabbit fiber with pH 10e11. After ozonation, the whiteness degree of these fibers increased 7% while it was 18% for the fibers at pH 2e3. Because in a basic solution, more hydroxide ions are present and these hydroxide ions act as an initiator for the decay of ozone, and lower pH levels were often more efficient with respect to decolorization efficiency likely due to selective ozone reactions targeting chromophoric bonds in the colored materials [24e26]. On the other hand, no significant difference between neutral and acidic fiber’s ozonation was observed. It is recommended to ozonate Angora rabbit fiber without any pH adjustment, because the ozonation of fiber is more economic and easy to study in neutral pH than in acidic pH.
3.1.4. FT-IR Chemical composition of wool underwent significant changes during ozonation. Hence, untreated and ozonated Angora samples were analyzed by considering some chemical groups using FT-IR spectroscopy. These groups are presented in Table 2. The spectrum consists of many broad bands. The band at 3264 cm1 was attributed to the eOH stretching vibrations [27]. Ozonated Angora fiber showed a reduction in eOH stretching absorbance and shifting of the peak position from 3264.9 cm1 to 3274.36 cm1. Bands for amide I (1633 cm1), amide II (1516 cm1), and amide III (1232 cm1) were also observed in the spectrum. However, the transmittance values of these bands increased and showed shifting of the peak position from 1633 cm1, 1516 cm1, and 1232 cm1 to 1652.5 cm1, 1531.66 cm1, and 1169.17 cm1, respectively, after ozonation. The band at 1445 cm1 disappeared in the spectra of ozonated Angora fiber. It is thought that the eCH deformation of CH2 and CH3 stretching modes occurred during ozonation. This situation can be related to the initial and most rapid reaction of ozone with the olefin groups, and then with the aromatic nuclei. In the absence or inaccessibility of these structures, ozone will also react with many different carbonehydrogen bonds [17,28]. That is why the band at 1445 cm1 disappeared after ozonation. The results show that the ozonation process produced a significant increase in the cysteic acid signal at 1040 cm1 in the FT-IR spectra of the ozonated Angora, but no peak was observed in the untreated Angora’s spectra (Table 2). The ozonation modified the Angora surface as indicated by the increase in cysteic acid signal intensities. The major oxidative product of the ozonated Angora was the cysteic acid species. This indicates a reduction in the disulphide bonds. Also, there was a significant increase in the CeS transmittance value at 667 cm1 after ozonation. Finally, ozone oxidized cystine linkage present in the Angora fiber’s surface to cysteic acid, and an improvement in dyeability and chemical damage was observed [27,29e31]. This is in good agreement with the test results of the Angora fiber’s damage determination, and correlates with the observed significant improvement in dyeability. 3.1.5. Determination of Angora fiber’s damage Microscopic views of untreated and ozonated Angora rabbit fiber that was immersed in chlorine water were considered in investigating the damage to the outer layers (epicuticle).
16
Table 2 Infrared transmittance peaks (cm1) of untreated and ozonated Angora rabbit fiber [24e27]
14
Possible Assignment
Ozonated
Untreated
12
OH stretching Amide I Amide II CH2 and CH3 stretching Amide III Cystine dioxide Cysteic acid CeS stretching
3274.36 1652.5 1531.66 e e 1169.17 1040.1 667.92
3264.9 1633.19 1516.15 1445.67 1232.14 e e 667.92
18
Whiteness Change (%)
1903
10 8 6 pH 2-3
pH 7
pH 10-11
Fig. 4. Effect of empregnated water pH on whiteness degree.
1904
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906
As shown in Fig. 5, bubbles or blisters known as AllwTrden sacs were formed on either side of the fiber’s surface. However, the ozonated fiber surface showed up by lessening the size of the blisters. This means that the ozonation process caused the damage on the Angora fiber’s surface. This result was also supported by the solubility test. While the untreated Angora rabbit fiber had about 13.5% solubility, ozonated Angora rabbit fiber and conventionally bleached Angora rabbit fiber had about 41.4 and 17% solubility, respectively. Hence, the Angora rabbit fiber was significantly damaged by ozone. Also, SEM photographs of untreated and ozonated Angora rabbit fiber supported it. It was seen that the roughness occurred on the cuticule of the ozonated fiber (Fig. 6). In other words, the outer layer of Angora rabbit fiber was damaged by ozone. Meanwhile, after dyeing, the cuticule layer of the Angora fiber was removed completely. 3.1.6. Effect of ozonation on dyeing properties of Angora rabbit fiber CIELab L*, a*, b*, and K/S values of dyed Angora rabbit fibers (untreated and ozonated) are illustrated in Table 3. Moreover, the photographs of untreated and treated Angora samples were taken for better explanation and are provided in Fig. 7 in which the most evident dye uptake was obtained with the fiber ozonated at 60% WPV and pH 7 for 45 min. The results clearly indicate that ozonation treatment increased the color yields considerably (Fig. 7). The difficulties in soaking Angora rabbit wool and their closed structure make the dye uptake difficult under normal conditions. Although Angora rabbit fiber has a closed structure, the epicuticule layer, which plays the role of a barrier for dye uptake, as it can be seen from the SEM photographs, with the ozone blunted sharp edges, of the epicuticule layer and caused lines on the fiber’s surface. Consequently, the epicuticule layer became thinner compared to the untreated one, and so the dye uptake became easier. Meanwhile, the ozone oxidized cystine linkage present in the Angora rabbit fiber surface to cysteic acid and an improvement in dyeability were observed.
The K/S value of untreated fiber increased from 4.45 to 22.59 when ozonation process was carried out for 45 min with the fiber at 60% WPV and pH 7, on the other hand the K/S value of conventionally bleached one is 4.403. As shown in Fig. 7, the K/S value, which represents the color efficiency, was affected due to ozonation time, WPV, and pH values during ozonation. When Angora rabbit fiber was ozonated for longer treatment time and then dyed, higher K/S values were observed. For example, when the fiber at 60% WPV and pH 7 was ozonated for 5, 10, 15, 30, and 45 min and then dyed, the K/S values observed were 5.7, 14.2, 16.6, 21.6, and 22.4, respectively. After fixing the treatment time at 45 min, the effect of WPV and pH during ozonation on the dyeability of the fiber was investigated. The maximum increase in K/S value was obtained by the Angora rabbit fiber that was dyed after ozonation for 45 min at pH 7 and 60% WPV. However, the K/S value started to decrease when the WPV of fiber increased more than 60% during ozonation. For instance, the K/S value of dyed fiber that ozonated with 80 and 100% WPV was 19.95 and 19.75, respectively. In other words, the K/S value of Angora fibers that ozonated and then dyed increased with the increase in the WPV until a critical value (60%) during ozonation. After this critical value, the increase in the WPV of Angora fibers had a negative effect on color efficiency. Meanwhile, the pH of the Angora rabbit fiber during ozonation did not have a significant effect on the dye uptake. The K/S value of the Angora rabbit fiber that was ozonated at different pH (2e3, 7, 10e11) was about 22. 4. Conclusions Angora rabbit fiber production has great importance in the world animal fiber production. Angora fabrics find usage in health products, for the benefit of arthritis patients, and for thermal underwear in cold climates because of its warm nature. Owing to the sensitive nature of the Angora fiber, during processes like washing, bleaching, and dyeing, these fibers
Fig. 5. Microscopic views of blisters occurred on untreated (I) and ozonated (II) Angora fiber.
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906
1905
Fig. 6. SEM photographs of untreated (I), ozonated (II), and ozonated þ dyed Angora rabbit fiber (III). Table 3 % Reflectance and K/S value of untreated and ozonated Angora rabbit fibers followed by dyeing Sample specification
L*
a*
b*
K/S
Untreated Bleached with hydrogen peroxide
41.516 41.690
1.437 2.192
20.057 20.935
4.459 4.403
Treatment time pH (min) Ozonated 45 45 45 45 45 45 45 5 10 15 30 45
WPV
7 20 7 40 7 60 7 80 7 100 2e3 60 10e11 60 7 60 7 60 7 60 7 60 7 60
23.058 20.584 18.578 19.799 19.691 19.06 19.638 37.543 25.913 24.816 17.887 18.478
3.685 3.367 2.693 2.275 2.729 2.474 3.193 1.544 3.623 3.477 3.629 2.493
17.868 17.228 13.037 15.754 12.462 14.391 16.269 18.784 21.144 18.963 15.186 13.067
16.375 20.470 22.595 19.952 19.758 22.595 22.052 5.713 14.260 16.689 21.650 22.475
must be handled cautiously. Therefore, the ozonation process that requires low temperature was investigated in this study in terms of the Angora rabbit fiber’s bleaching efficiency and dyeability properties. From the experiments it was observed that, in the ozonation process, there was an increase in the whiteness degree and dyeability property of Angora rabbit fiber with increasing ozonation time. The study showed that the best whiteness degree and color yields were obtained by ozonation at 23e25 C of an Angora rabbit fiber impregnated with water at pH 7 and 60% WPV. Ozonation time must be adjusted according to the required whiteness degree and color yields. Moreover, FT-IR results showed the ozone oxidized cystine linkage present in the Angora fiber surface to cysteic acid and an improvement in dyeability. Chemical damage can be observed after ozonation. SEM photographs and damage analysis supported this result. According to SEM photographs, it can be said that ozone processes damaged the outer layer of the Angora fiber surface. Finally, ozone provided a good improvement in the
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S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906
Fig. 7. The picture of untreated and ozonated Angora rabbit fiber.
degree of whiteness and color yields. However, the amount of damage caused by ozone must be considered. In view of environmental requirements, ozonation process within closed system is environmentally acceptable, because during ozonation a very low quantity of water is consumed and bleaching is achieved in a very short time at room temperature. Acknowledgment We thank the Department of Materials Science and Engineering at the Faculty of Engineering and Architecture of the University of Anadolu for the SEM photographs and our ¨ zevin and O ¨ zgu¨r Atalay for their kind help students Kemal O during the experiments. References [1] Voyvoda H, Ulutas B, Eren H, Karagenc T, Bayramlı G. Vet Dermatol 2005;16:285e8. [2] Schlink AC, Liu SM. A report for the Rural Industries Research and Development Corporation; 2003. [3] http://kws.atlantia.sca.org/Favorite_Fibers_of_Handspinners.pdf; 2007. [4] http://en.wikipedia.org/wiki/Angora_rabbit#column-one; 2007. [5] Elmas M, Uney K, Karabacak A, Yazar E. Bull Vet Inst Pulawy 2005;49:85e8. [6] Ossard H, The´bault R-G, Vrillon J-L, Allain D, Rochambeau H. Eur Fine Fibre Netw 1995;5:35e47. [7] http://www.sac.ac.uk/consultancy/farmdiversification/database/ novellivestock/angorarabbits; 2007. [8] http://en.wikipedia.org/wiki/Angora_rabbit; 2007. [9] Robertson J. Forensic examination of fibers. In: Robertson James, Grieve Michael, editors. 2nd ed. London, UK: CRC Press; 1999. [10] http://www.ipr.res.in; 2006. [11] http://ressources.ciheam.org/om/pdf/c08/95605323.pdf; 2007.
[12] Atav R, Ozdogan E. Tekstil ve Konfeksiyon 2004;14:75. [13] Yurdakul A, Akc¸akoca EP, Atav R, Gu¨ler F. Tekstil ve Mu¨hendis 2006;1:59e60. [14] Welham AC. Wool dyeing. In: Lewis DM, editor. West Yorkshire, UK: Staples Printers Rochester Ltd.; 1992. p. 104e5. [15] Dalton J, Franck R. Silk, mohair, cashmere and other luxury fibres [Cambridge, England, Woodhead Pub.]. In: Franck RR, editor. Boca Raton, FL: CRC Press; 2001. p. 163. [16] Karmakar SR. Chemical technology in the pretreatment processes of textiles. 1st ed. Amsderdam, Netherlands: Elsevier Science B.V.; 1999. p. 174. [17] Perincek S. An investigation on the applicability of ultrasound, ultraviolet, ozone and combination of these technologies as a pretreatment process. MSc Thesis, Ege University, BornovaeIzmir; 2006. _ Ko¨rlu¨ AE, Duran K. AATCC Rev [18] Perincek S, Bahtiyari MI, 2007:36e41. [19] http://www.usace.army.mil/usace-docs/eng-tech-ltrs/etl1110-1-161; 2006. [20] AllwTrden KV. Z Angew Chem 1916;29:79. [21] Lazzaroni M, Pezzotta E, Mendmi G, Bocchiola D, Ward D. IEEE 2000:478e82. ¨ zdemir D. A research on alternative processes for the bleaching of [22] O denim garments by sodium hypochlorite and potassium permanganate. MSc Thesis, Ege University, BornovaeIzmir; 2006. [23] Prabaharan M, Chandran NR, Selva KN, Venkata RJ. Coloration Technol 2000;116:83e6. [24] Iglesias SC. Degradation and biodegradability enhancement of nitrobenzene and 2,4-dichlorophenol by means of advanced oxidation processes based on ozone. PhD Thesis, Universitat De Barcelona; 2002. [25] Adams CD, Gorg S. J Environ Eng 2002;128:293e8. [26] http://www.lenntech.com/ozone.htm; 2006. [27] Kim J, Lewis DM. Coloration Tech 2002;118:181e4. [28] Lyse TE. A study on ozone modification of lignin in alkali-fiberized wood. PhD Thesis, Lawrence University; 1979. [29] Cardamone JM, Nu~nez A, Ashby R, Dudley R. Textile Res J 2006;76:99e108. [30] El-Zaher NA, Micheal MN. J Appl Polym Sci 2002;85:1469e76. [31] Shao J, Liu J, Carr CM. Coloration Technol 2001;117:270e5.
Journal of Cleaner Production 16 (2008) 1900e1906 www.elsevier.com/locate/jclepro
Ozone treatment of Angora rabbit fiber _ Bahtiyari b, A.E. Ko¨rlu¨ b,*, K. Duran b S. Perincek a, M.I. b
a _ Emel Akın Vacational High School, Izmir, Turkey _ Department of Textile Engineering, Ege University, Ege University Campus, Bornova, Izmir 35100, Turkey
Received 20 October 2007; received in revised form 31 December 2007; accepted 15 January 2008 Available online 10 March 2008
Abstract The aim of this study was to investigate a novel bleaching technique for Angora rabbit fiber. For this purpose, a detailed investigation on the role of the fiber moisture, pH, and treatment time during ozonation was carried out. Also, the effect of ozonation on the dyeing properties of Angora rabbit fibers was researched. Consequently, it was found that ozonation improved the degree of whiteness and dyeability of Angora rabbit fiber. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Ozone; Angora rabbit fiber; Oxidative bleaching; Finishing; Dyeing; FT-IR; SEM
1. Introduction Angora is a keratinous textile material, produced by the long-haired Angora rabbit [1]. The Angora rabbit (Oryctolagus cuniculus) is a very old breed of rabbit and a species of the order Lagomorpha, believed to have originated from Ankara, Turkey [1e5]. The Romans bred Angora rabbits and the modern Angora rabbit industry dates from the 1700s. Until 1965, France was the leading producer; the world market is now dominated by fiber produced in China. The other producers are France, Chile, Argentina, Hungary, Germany, Finland, and India [2,6]. Production of the Angora fiber is the result of a pair of autosomal and recessive genes that cause an extension of the active phase in the hair follicle from the normal 5e7 weeks in fur rabbits to 12e16 weeks in Angora rabbits [2]. White Angora has been favored in selection because of the associated ease of dyeing. However, the move towards naturally colored fiber is evident in Angora as in other fiber markets [7]. There are different Angora rabbit breeds according to which the colors can change from white to black (blue, chocolate, fawn, tortoise, chinchilla, sable, and chestnut) [8]. * Corresponding author. Tel./fax: þ90 232 339 92 22. E-mail address: [email protected] (A.E. Ko¨rlu¨). 0959-6526/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2008.01.005
Angora fiber can be used in several ways. Knitted product is the common fabric type produced, as the bristle content of most Angora fleeces makes it unsuitable for the production of next-to-skin wear or high quality suiting material. The warm nature of Angora fabrics makes it suitable for use in health products for the benefit of arthritis patients and for thermal underwear in cold climates. Angora fiber is usually blended with another fiber such as wool to improve its performance, both in processing and fabric wearability [2]. Rabbit hair is obtained from the pelts of the Angora rabbit. The hair is shorn from the pelts and separated by blowing [9]. This fiber is one of the ‘‘luxury fine fibers,’’ which also include mohair, cashmere, and alpaca. These luxury wools only represent 3% of the world’s clean wool production, but their price can be 10e30 times more than that of sheep wool. Several factors contribute to this difference, including their toughness, lightness, fineness, softness, and their image and reputation [2,6]. Angora fiber has the chemical structure of protein. It consists of spindle-shaped cortical cells [10]. Angora is a medullated fiber, which makes it lightweight and slick. It is as fine as the best cashmere, that is, about 14e16 mm. Angora is a heterotypic fleece. It contains 1% coarse hair called bristles. However, unlike other textile fleeces (especially mohair), bristles are considered desirable, as they prevent felting and impart the characteristic fluffiness [2,6,10,11]. Angora fiber
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has a low density of about 1.15e1.18 g/cm3, compared to 1.33 g/cm3 for wool and 1.50 g/cm3 for cotton. This makes the Angora garments very light, but warm [2,10]. However, the smooth surface and low inter-fiber friction leads to shedding. Because of smoothness (low friction coefficient), weaving with pure Angora wool becomes difficult [9,10]. The fibers themselves are very clean, as the rabbits produce only 2% of their fiber weight in skin excretions, and also because rabbits clean their own fur. Hence, Angora rabbit fibers do not need scouring. However, in some cases bleaching processes can be carried out. The main bleaching agents for wool are oxidizing and reducing agents, which can also be used for Angora rabbit fibers. However, during the processes like washing, bleaching, and dyeing, these fibers must be processed cautiously because, in the lengthwise view of Angora fibers, the most important issue that attracts attention is the ladder or the beadlike structure of the medulla. For this reason, Angora wool can be treated at a temperature of 70 C to protect the fibers [12e16]. On the other hand, legal restrictions and the national and the international awareness of ecology and pollution control allow new advanced techniques (advanced oxidation processes) and technologies to be used. Therefore, the ozonation process, which requires low temperature [17e19], was investigated in this study in terms of the Angora fiber’s bleaching efficiency and dyeability properties. 2. Experiment Angora rabbit fiber (fineness ¼ 16.26 mm) was used in these experiments. The whiteness degree according to the Stensby formula for raw Angora rabbit fiber is 49.2. In this study, the effect of the rinsing process that was performed after ozonation, the fiber’s water pickup value (WPV) (Eq. (1)), pH, the effect of ozonation time on the whiteness degree was investigated. The effect of the ozonation process on the dyeability of the Angora fiber was researched. The WPV of fibers, which were conditioned at 65% moisture and 20 C, was adjusted to the required value and then ozonated at 25 C for the required time.
Moreover, the effect of the fiber’s WPV at different treatment times was also researched. The WPV was set at 0, 20, 40, 60, 80, and 100%. Also, the ozonation time was set at 5, 10, 15, 30, and 45 min. During these experiments, the ambient temperature and the fiber’s pH were adjusted to 23e25 C and 7, respectively. After the optimization of WPV, the effect of pH (2e3, 7, and 10e11) was studied with fiber at 60% WPV. After all the treatments, the samples were rinsed with water at 50 C for 5 min without the use of any chemicals. At the same time, soft mill water (permuted water) was used in all the experiments. On the other hand, conventional hydrogen peroxide bleaching was carried out in accordance with the recipes in Table 1. Finally, ozonated Angora fibers were dyed with a Milling dyestuff Supranol Fastcyanin GR (C.I. Acid Blue 120) according to Fig. 1 for investigating the effect of ozonation on the dyeing properties of the Angora fiber. As shown in Fig. 1, the material was soaked in the solution at 40 C for 10 min, and then the temperature was raised to 70 C in 30 min. At this temperature, the fibers were treated for 30 min. Then, the dye bath was cooled and the Angora fibers were removed. Then the dyed samples were rinsed in cold (50 ), hot (100 at 50 C), and cold (100 ) water, respectively, and dried at an ambient temperature. The equipment used for ozone bleaching has three components: the ozone generator, the applicator, and the ozone destroyer. The system is fully closed because of the harmful effects of ozone on health. The capacity of the ozone generator (Lundell Aquametrics, Inc.) is 0e5 L/min. Oxygen is supplied to the generator from an oxygen tube and the generator supplies the required ozoneeoxygen mixture to the applicator. The applicator is a cylindrical glass tube with a diffuser at the bottom. In these experiments, the flow rate of the ozone was 1.5 L/min. The Angora samples were placed in the applicator for the required time. To evaluate the results obtained, whiteness change (%), color yields (K/S ), and the damage to the fibers were determined. The whiteness degrees of the samples were examined with a Minolta 3600d spectrophotometer according to the
Weight of impregnated fabric Weight of greige fabric W:P:V: % ¼ 100 Weight of greige fabric
Experiments were carried out in two stages. In the first stage, for investigating the effects of rinsing on the whiteness degree, the Angora fiber with 60% WPV was ozonated for 45 min and the whiteness degree was evaluated before rinsing. Then, the Angora sample was separated into two portions. One of them was rinsed with water at 50 C for 5 min and then set aside for 2 weeks. The other one was set aside for 2 weeks without rinsing. Afterwards, the whiteness degree of the samples set aside were measured and compared.
1901
ð1Þ
Table 1 Hydrogen peroxide bleaching Sodium pyrophosphate NH3 Gisapol ECO 160 H2O2 (35%) Cottozon 98106 L.R. (1:20)
2.0 g/l pH 9e9.5 2.0 g/l 20.0 ml/l 2.0 ml/l 55 C, 90 min
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1902
Fig. 1. Dyeing of Angora rabbit fiber.
Stensby formula and then the changes in whiteness (Eqs. (2) and (3)) were evaluated. Whiteness ðStensbyÞ ¼ L þ 3a 3b
ð2Þ
Whiteness changeðWC Þ ¼ WAfter treatment Þ WBefore treatment 100= WBefore treatment ð3Þ Also, for evaluating the effects of ozonation on the dyeing properties of Angora fibers, CIELab L*, a*, and b* values of samples were measured with Minolta 3600d spectrophotometer (D 65/10 ) and color yields (K/S ) of dyed samples were calculated using the Kubelka Munk equation. Microscopic and solubility tests were performed for investigating the damage to the Angora fiber due to ozonation. Damage to the outer layers (epicuticle) may be revealed by means of the AllwTrden reaction. When fibers are immersed in chlorine or bromine water, bubbles or blisters known as AllwTrden sacs are formed on the surface. Damage to the fiber surface may show up by lessening the size of, or eliminating altogether, the blisters [20]. Alkali solubility values were determined by the ASTM D1283 standard test method. It was calculated as a percentage of the original mass, according to Eq. (4) given here: Alkali solubility% ¼ ðM1 M2 Þ=M1 100
ð4Þ
where M1 e mass of oven-dry samples before sodium hydroxide treatment, and M2 e mass of oven-dry samples after sodium hydroxide treatment. Furthermore, Fourier transform infrared spectroscopy (FTIR) of the Angora fiber was carried out with a Perkin Elmer Spectrum 100. 3. Results and discussion
[17,18,22]. Hence, the effects of rinsing on the whiteness degree were investigated. To establish the results, the whiteness degrees of the rinsed and the unrinsed ozonated Angora samples were measured after 2 weeks. It was found that the Angora rabbit fiber ozonated and rinsed afterward showed a loss of 8.9% in the degree of whiteness while the loss was 25.6% for the unrinsed samples. Finally, it can be said that if the rinsing process was not carried out after ozonation, the whiteness degree of Angora rabbit fiber decreased drastically everyday. Finally, after all the treatments the fibers were rinsed with water at 50 C for 5 min.
3.1.2. Effect of fiber’s WPV and treatment time on whiteness degree of Angora rabbit fiber Today, it is well known from literature and research that the water content of the material is of great importance in terms of the ozonation efficiency [17,18,22,23]. That is why fibers were impregnated with six different water pickup values (0, 20, 40, 60, 80, and 100%) at this stage of the experiments. For investigating the water content’s effects on ozonation efficiency of Angora rabbit fiber, treatment time and the WPV were set to 45 min and 7, respectively. It can be seen from Fig. 2 that the whiteness degree of Angora rabbit fiber after ozonation increased with the rise in the WPV of fibers until a critical pickup value. An interesting point is that the increase in the whiteness degree was the highest when the WPV was about 60%. The 18% increase in whiteness after ozonation for 45 min of the fibers at 60% WPV could not be reached by the fibers with other pickup values. After this critical value, the increase in the WPV of fibers caused a gradual decrease in the whiteness degree. It was found thus that the WPV of fibers had an important effect on the whiteness degree. It is considered that the positive effect of water content of Angora fibers on the whiteness degree is the penetration of ozone gas into the fiber [17,18]. The increase in the water content up to 60% provides penetration of ozone gas into the fiber readily. But after this value of water content, the decomposition of ozone in water gathers speed and the whiteness degree starts to reduce. Hence, it is recommended to ozonate fibers in 60% WPV for optimum effect. After the optimization of Angora rabbit fiber’s WPV, the role of treatment time and pH during ozone bleaching of Angora rabbit fibers were studied (Figs. 3 and 4). All experiments were realized at 45 min and 60% pickup of water.
3.1. Optimization of ozonation treatment 3.1.1. Effect of rinsing process on whiteness degree of ozonated Angora rabbit fiber The removal of soil from the surface of the fabric by the washing process is of prime importance for the efficiency of subsequent processes [21]. Hence, large-scale finishing processes were conducted with rinsing to remove unfixed dye or by-products from the fabric’s surface. In some researches and literature, it was highlighted that during the rinsing process, the by-products that are responsible for the re-yellowing of textile materials after ozonation migrates to the rinsing bath
Fig. 2. Effect of Angora rabbit fibre’s WPV on whiteness degree.
Whiteness Change (%)
S. Perincek et al. / Journal of Cleaner Production 16 (2008) 1900e1906 20 15 10 5 0 5 min.
10 min.
15 min.
30 min.
45 min.
Fig. 3. Effect of treatment time on whiteness degree.
It is essential to identify the treatment time for the desired bleaching effect of ozonation like other finishing processes. To investigate the effects of ozonation time on the degree of whiteness of the Angora rabbit fiber, it was decided to ozonate the Angora fibers for 5, 10, 15, 30, and 45 min. During ozonation, all samples were at 60% WPV. It was realized that the whiteness degree of Angora rabbit fiber increased with increase in ozonation time. 3.1.3. Effect of empregnated water’s pH on whiteness degree of Angora rabbit fiber The other parameter that affects the ozonation efficiency is the pH of the water that is used in impregnation of Angora rabbit fiber (Fig. 4). Three different pH values (pH 2e3 with buffer acid, 7 with distillated water, 10e11 with caustic soda) were studied in the experiments. During the experiments the tested fiber’s pH was 7.2. According to the results, the ozonation efficiency was restricted in the basic pH values when compared to acidic and neutral pH. Consequently, the lowest whiteness degree was obtained from Angora rabbit fiber with pH 10e11. After ozonation, the whiteness degree of these fibers increased 7% while it was 18% for the fibers at pH 2e3. Because in a basic solution, more hydroxide ions are present and these hydroxide ions act as an initiator for the decay of ozone, and lower pH levels were often more efficient with respect to decolorization efficiency likely due to selective ozone reactions targeting chromophoric bonds in the colored materials [24e26]. On the other hand, no significant difference between neutral and acidic fiber’s ozonation was observed. It is recommended to ozonate Angora rabbit fiber without any pH adjustment, because the ozonation of fiber is more economic and easy to study in neutral pH than in acidic pH.
3.1.4. FT-IR Chemical composition of wool underwent significant changes during ozonation. Hence, untreated and ozonated Angora samples were analyzed by considering some chemical groups using FT-IR spectroscopy. These groups are presented in Table 2. The spectrum consists of many broad bands. The band at 3264 cm1 was attributed to the eOH stretching vibrations [27]. Ozonated Angora fiber showed a reduction in eOH stretching absorbance and shifting of the peak position from 3264.9 cm1 to 3274.36 cm1. Bands for amide I (1633 cm1), amide II (1516 cm1), and amide III (1232 cm1) were also observed in the spectrum. However, the transmittance values of these bands increased and showed shifting of the peak position from 1633 cm1, 1516 cm1, and 1232 cm1 to 1652.5 cm1, 1531.66 cm1, and 1169.17 cm1, respectively, after ozonation. The band at 1445 cm1 disappeared in the spectra of ozonated Angora fiber. It is thought that the eCH deformation of CH2 and CH3 stretching modes occurred during ozonation. This situation can be related to the initial and most rapid reaction of ozone with the olefin groups, and then with the aromatic nuclei. In the absence or inaccessibility of these structures, ozone will also react with many different carbonehydrogen bonds [17,28]. That is why the band at 1445 cm1 disappeared after ozonation. The results show that the ozonation process produced a significant increase in the cysteic acid signal at 1040 cm1 in the FT-IR spectra of the ozonated Angora, but no peak was observed in the untreated Angora’s spectra (Table 2). The ozonation modified the Angora surface as indicated by the increase in cysteic acid signal intensities. The major oxidative product of the ozonated Angora was the cysteic acid species. This indicates a reduction in the disulphide bonds. Also, there was a significant increase in the CeS transmittance value at 667 cm1 after ozonation. Finally, ozone oxidized cystine linkage present in the Angora fiber’s surface to cysteic acid, and an improvement in dyeability and chemical damage was observed [27,29e31]. This is in good agreement with the test results of the Angora fiber’s damage determination, and correlates with the observed significant improvement in dyeability. 3.1.5. Determination of Angora fiber’s damage Microscopic views of untreated and ozonated Angora rabbit fiber that was immersed in chlorine water were considered in investigating the damage to the outer layers (epicuticle).
16
Table 2 Infrared transmittance peaks (cm1) of untreated and ozonated Angora rabbit fiber [24e27]
14
Possible Assignment
Ozonated
Untreated
12
OH stretching Amide I Amide II CH2 and CH3 stretching Amide III Cystine dioxide Cysteic acid CeS stretching
3274.36 1652.5 1531.66 e e 1169.17 1040.1 667.92
3264.9 1633.19 1516.15 1445.67 1232.14 e e 667.92
18
Whiteness Change (%)
1903
10 8 6 pH 2-3
pH 7
pH 10-11
Fig. 4. Effect of empregnated water pH on whiteness degree.
1904
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As shown in Fig. 5, bubbles or blisters known as AllwTrden sacs were formed on either side of the fiber’s surface. However, the ozonated fiber surface showed up by lessening the size of the blisters. This means that the ozonation process caused the damage on the Angora fiber’s surface. This result was also supported by the solubility test. While the untreated Angora rabbit fiber had about 13.5% solubility, ozonated Angora rabbit fiber and conventionally bleached Angora rabbit fiber had about 41.4 and 17% solubility, respectively. Hence, the Angora rabbit fiber was significantly damaged by ozone. Also, SEM photographs of untreated and ozonated Angora rabbit fiber supported it. It was seen that the roughness occurred on the cuticule of the ozonated fiber (Fig. 6). In other words, the outer layer of Angora rabbit fiber was damaged by ozone. Meanwhile, after dyeing, the cuticule layer of the Angora fiber was removed completely. 3.1.6. Effect of ozonation on dyeing properties of Angora rabbit fiber CIELab L*, a*, b*, and K/S values of dyed Angora rabbit fibers (untreated and ozonated) are illustrated in Table 3. Moreover, the photographs of untreated and treated Angora samples were taken for better explanation and are provided in Fig. 7 in which the most evident dye uptake was obtained with the fiber ozonated at 60% WPV and pH 7 for 45 min. The results clearly indicate that ozonation treatment increased the color yields considerably (Fig. 7). The difficulties in soaking Angora rabbit wool and their closed structure make the dye uptake difficult under normal conditions. Although Angora rabbit fiber has a closed structure, the epicuticule layer, which plays the role of a barrier for dye uptake, as it can be seen from the SEM photographs, with the ozone blunted sharp edges, of the epicuticule layer and caused lines on the fiber’s surface. Consequently, the epicuticule layer became thinner compared to the untreated one, and so the dye uptake became easier. Meanwhile, the ozone oxidized cystine linkage present in the Angora rabbit fiber surface to cysteic acid and an improvement in dyeability were observed.
The K/S value of untreated fiber increased from 4.45 to 22.59 when ozonation process was carried out for 45 min with the fiber at 60% WPV and pH 7, on the other hand the K/S value of conventionally bleached one is 4.403. As shown in Fig. 7, the K/S value, which represents the color efficiency, was affected due to ozonation time, WPV, and pH values during ozonation. When Angora rabbit fiber was ozonated for longer treatment time and then dyed, higher K/S values were observed. For example, when the fiber at 60% WPV and pH 7 was ozonated for 5, 10, 15, 30, and 45 min and then dyed, the K/S values observed were 5.7, 14.2, 16.6, 21.6, and 22.4, respectively. After fixing the treatment time at 45 min, the effect of WPV and pH during ozonation on the dyeability of the fiber was investigated. The maximum increase in K/S value was obtained by the Angora rabbit fiber that was dyed after ozonation for 45 min at pH 7 and 60% WPV. However, the K/S value started to decrease when the WPV of fiber increased more than 60% during ozonation. For instance, the K/S value of dyed fiber that ozonated with 80 and 100% WPV was 19.95 and 19.75, respectively. In other words, the K/S value of Angora fibers that ozonated and then dyed increased with the increase in the WPV until a critical value (60%) during ozonation. After this critical value, the increase in the WPV of Angora fibers had a negative effect on color efficiency. Meanwhile, the pH of the Angora rabbit fiber during ozonation did not have a significant effect on the dye uptake. The K/S value of the Angora rabbit fiber that was ozonated at different pH (2e3, 7, 10e11) was about 22. 4. Conclusions Angora rabbit fiber production has great importance in the world animal fiber production. Angora fabrics find usage in health products, for the benefit of arthritis patients, and for thermal underwear in cold climates because of its warm nature. Owing to the sensitive nature of the Angora fiber, during processes like washing, bleaching, and dyeing, these fibers
Fig. 5. Microscopic views of blisters occurred on untreated (I) and ozonated (II) Angora fiber.
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1905
Fig. 6. SEM photographs of untreated (I), ozonated (II), and ozonated þ dyed Angora rabbit fiber (III). Table 3 % Reflectance and K/S value of untreated and ozonated Angora rabbit fibers followed by dyeing Sample specification
L*
a*
b*
K/S
Untreated Bleached with hydrogen peroxide
41.516 41.690
1.437 2.192
20.057 20.935
4.459 4.403
Treatment time pH (min) Ozonated 45 45 45 45 45 45 45 5 10 15 30 45
WPV
7 20 7 40 7 60 7 80 7 100 2e3 60 10e11 60 7 60 7 60 7 60 7 60 7 60
23.058 20.584 18.578 19.799 19.691 19.06 19.638 37.543 25.913 24.816 17.887 18.478
3.685 3.367 2.693 2.275 2.729 2.474 3.193 1.544 3.623 3.477 3.629 2.493
17.868 17.228 13.037 15.754 12.462 14.391 16.269 18.784 21.144 18.963 15.186 13.067
16.375 20.470 22.595 19.952 19.758 22.595 22.052 5.713 14.260 16.689 21.650 22.475
must be handled cautiously. Therefore, the ozonation process that requires low temperature was investigated in this study in terms of the Angora rabbit fiber’s bleaching efficiency and dyeability properties. From the experiments it was observed that, in the ozonation process, there was an increase in the whiteness degree and dyeability property of Angora rabbit fiber with increasing ozonation time. The study showed that the best whiteness degree and color yields were obtained by ozonation at 23e25 C of an Angora rabbit fiber impregnated with water at pH 7 and 60% WPV. Ozonation time must be adjusted according to the required whiteness degree and color yields. Moreover, FT-IR results showed the ozone oxidized cystine linkage present in the Angora fiber surface to cysteic acid and an improvement in dyeability. Chemical damage can be observed after ozonation. SEM photographs and damage analysis supported this result. According to SEM photographs, it can be said that ozone processes damaged the outer layer of the Angora fiber surface. Finally, ozone provided a good improvement in the
1906
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Fig. 7. The picture of untreated and ozonated Angora rabbit fiber.
degree of whiteness and color yields. However, the amount of damage caused by ozone must be considered. In view of environmental requirements, ozonation process within closed system is environmentally acceptable, because during ozonation a very low quantity of water is consumed and bleaching is achieved in a very short time at room temperature. Acknowledgment We thank the Department of Materials Science and Engineering at the Faculty of Engineering and Architecture of the University of Anadolu for the SEM photographs and our ¨ zevin and O ¨ zgu¨r Atalay for their kind help students Kemal O during the experiments. References [1] Voyvoda H, Ulutas B, Eren H, Karagenc T, Bayramlı G. Vet Dermatol 2005;16:285e8. [2] Schlink AC, Liu SM. A report for the Rural Industries Research and Development Corporation; 2003. [3] http://kws.atlantia.sca.org/Favorite_Fibers_of_Handspinners.pdf; 2007. [4] http://en.wikipedia.org/wiki/Angora_rabbit#column-one; 2007. [5] Elmas M, Uney K, Karabacak A, Yazar E. Bull Vet Inst Pulawy 2005;49:85e8. [6] Ossard H, The´bault R-G, Vrillon J-L, Allain D, Rochambeau H. Eur Fine Fibre Netw 1995;5:35e47. [7] http://www.sac.ac.uk/consultancy/farmdiversification/database/ novellivestock/angorarabbits; 2007. [8] http://en.wikipedia.org/wiki/Angora_rabbit; 2007. [9] Robertson J. Forensic examination of fibers. In: Robertson James, Grieve Michael, editors. 2nd ed. London, UK: CRC Press; 1999. [10] http://www.ipr.res.in; 2006. [11] http://ressources.ciheam.org/om/pdf/c08/95605323.pdf; 2007.
[12] Atav R, Ozdogan E. Tekstil ve Konfeksiyon 2004;14:75. [13] Yurdakul A, Akc¸akoca EP, Atav R, Gu¨ler F. Tekstil ve Mu¨hendis 2006;1:59e60. [14] Welham AC. Wool dyeing. In: Lewis DM, editor. West Yorkshire, UK: Staples Printers Rochester Ltd.; 1992. p. 104e5. [15] Dalton J, Franck R. Silk, mohair, cashmere and other luxury fibres [Cambridge, England, Woodhead Pub.]. In: Franck RR, editor. Boca Raton, FL: CRC Press; 2001. p. 163. [16] Karmakar SR. Chemical technology in the pretreatment processes of textiles. 1st ed. Amsderdam, Netherlands: Elsevier Science B.V.; 1999. p. 174. [17] Perincek S. An investigation on the applicability of ultrasound, ultraviolet, ozone and combination of these technologies as a pretreatment process. MSc Thesis, Ege University, BornovaeIzmir; 2006. _ Ko¨rlu¨ AE, Duran K. AATCC Rev [18] Perincek S, Bahtiyari MI, 2007:36e41. [19] http://www.usace.army.mil/usace-docs/eng-tech-ltrs/etl1110-1-161; 2006. [20] AllwTrden KV. Z Angew Chem 1916;29:79. [21] Lazzaroni M, Pezzotta E, Mendmi G, Bocchiola D, Ward D. IEEE 2000:478e82. ¨ zdemir D. A research on alternative processes for the bleaching of [22] O denim garments by sodium hypochlorite and potassium permanganate. MSc Thesis, Ege University, BornovaeIzmir; 2006. [23] Prabaharan M, Chandran NR, Selva KN, Venkata RJ. Coloration Technol 2000;116:83e6. [24] Iglesias SC. Degradation and biodegradability enhancement of nitrobenzene and 2,4-dichlorophenol by means of advanced oxidation processes based on ozone. PhD Thesis, Universitat De Barcelona; 2002. [25] Adams CD, Gorg S. J Environ Eng 2002;128:293e8. [26] http://www.lenntech.com/ozone.htm; 2006. [27] Kim J, Lewis DM. Coloration Tech 2002;118:181e4. [28] Lyse TE. A study on ozone modification of lignin in alkali-fiberized wood. PhD Thesis, Lawrence University; 1979. [29] Cardamone JM, Nu~nez A, Ashby R, Dudley R. Textile Res J 2006;76:99e108. [30] El-Zaher NA, Micheal MN. J Appl Polym Sci 2002;85:1469e76. [31] Shao J, Liu J, Carr CM. Coloration Technol 2001;117:270e5.