纤维的应用

Fibers and Polymers 2011, Vol.12, No.1, 95-10395Modification of Natural Bamboo Fibers for Textile ApplicationsLifang Liu 1,2, Qianli Wang 1,2, Longdi Cheng 1,2, Jingfang Qian 1,2, and Jianyong Yu 1,3*1The Key Lab of Textile Science & Technology, Ministry of Education, Donghua University, Shanghai 201620, China2College of Textiles, Donghua University, Shanghai 201620, China 3Modern Textile Institute, Donghua University, Shanghai 200051, China(Received March 5, 2010; Revised August 6, 2010; Accepted September 25, 2010)Abstract: Natural bamboo fibers have excellent properties suggesting that there is a good potential for them to be used in tex-tiles; however, they have not received the attention that they deserve owing to their coarse and stiff quality. Therefore, a chemical method for extraction and modification of natural bamboo fibers for textile end uses were developed and optimized in this paper. The quality of natural bamboo fibers were characterized by their chemical composition, linear density, and tenacity. Experimental results show that the modified bamboo fibers are finer, with significant lower content of noncellulosic substances. The processing parameters are optimized as: 20 g/l NaOH, 3 g/l Na 5P 3O 10, 5 g/l Na 2SO 3, 3 g/l penetrating agent,with a fiber to liquid ratio of 1:10, at 100o C for 2 h, and the bamboo fiber thus produced has cellulose amount of 73.25%,fineness of 3.26 tex, average length of 44.5 mm, breaking elongation of 2.8% and tenacity of 2.41 cN/dtex. The result of this study may offer a possibility of developing natural bamboo fibers into practical applications in textiles.Keywords: Natural bamboo fiber, Chemical modification, Chemical composition, Linear density, TenacityIntroductionNatural cellulose fibers have received increasing attention because of their biodegradability and renewable resources in comparison to synthetic fibers [1-3]. Cotton and bast fibers,especially cotton fibers, are important textile materials,primarily because of their more cost-efficient production and nearly universal product possibilities [1]. However, regarding another abundant renewable biomass material, the natural bamboo fibers, they have not received the attention that they deserve owing to their coarse and stiff quality, although bamboo pulp viscose fibers, also called bamboo fibers sometimes, have already been used for textiles products [4].Natural bamboo fibers are extracted from bamboos which have long been widely used for constructional purpose, for the pulp and paper in industry, and also for the natural fibers reinforced composites [5,6]. Like bast fibers, such as flax,hemp, jute, and ramie, natural bamboo fibers morphologically exist as technical fibers consisted of elementary fibers (usually with length of 1.9mm and width of 15.3µm)concreted together by noncellulosic substances (lignin,hemicellulose, pectin, and so on) [1,5,7-11]. Although the noncellulosic substances are contributed to hold those very short elementary fibers together, they are also responsible for the coarse and stiff quality of natural bamboo fibers. The main task in producing natural bamboo fibers for textile applications is to partially remove noncellulosic substances without damage to the fiber cellulose. It should be remarked that the natural bamboo fibers have not been successfully applied for textile products until now; however, there is a good potential for their application in textiles regarding their excellent properties, such as aseptic properties, high absorbencyand hygroscopicity, good electrostatic, and ultraviolet resistant properties [1,3,12]. Therefore, it is very interesting to investigate the extraction and modification of natural bamboo fibers for textile end uses.Chemical, biological, mechanical methods, or their combin-ation are usually used to modify bast fibers, among which chemical method is used most commonly [10,13-17].Chemical method is based on the mechanism that the cellulosic fibrils and noncellulosic substances have different stability in alkaline solution. It is a rapid and efficient process compared to that of biological or mechanical method, which usually involves the soaking of bast fibers in aqueous alkaline solutions, such as the solution of sodium hydroxide (NaOH), potassium hydroxide (KOH), and sodium carbonate (Na 2CO 3) [16]. Experiments showed the cheap and commercial available NaOH can dissolve and remove non-cellulosic substances by a swelling reaction without observable decomposition of cellulosic fibrils, so as to make the fiber finer, softer, and more suitable for textile processing [16,17].As for natural bamboo fibers, chemical method is also used most commonly. Kushwaha and Kumar [18] treated bamboo strips with NaOH solution with different concen-tration of 1~25% for 30 min at room temperature (20o C),and found that the composites have better mechanical properties at 5% of NaOH. Das et al. [19-21] conducted alkali treatments on bamboo strips with caustic soda solution with varying concentration (10, 15, 20, and 50%) for 1 h at ambient temperature. However, all of those researches were conducted on bamboo strips for the enhancement of composites; regarding the extraction of natural bamboo fibers for textiles end uses, there are little relative reports.Therefore, the chemical method is applied in this paper to extract and modify natural bamboo fibers. NaOH is also*Corresponding author: yu_jianyong@DOI 10.1007/s12221-011-0095-396Fibers and Polymers 2011, Vol.12, No.1Lifang Liu et al.selected to extract finer fibers, and its concentration is optimized in terms of fiber characteristics. Moreover, three additives, Na 5P 3O 10, Na 2SiO 3, and penetrating agent are also introduced to enhance the effects of NaOH, and their concentrations are optimized by orthogonal design method.Furthermore, the optimum treating temperature and time are also discussed to produce natural bamboo fibers with improved quality. The present study aims at offering a possibility of developing natural bamboo fibers into practical applications in textiles.ExperimentalMaterialsThe bamboo strips used to extract fibers in this study were split from the stems of natural bamboo produced in China.This bamboo as shown in Figure 1, which belongs to Phyllostachys Pubescens , was dried for more than 1 year in ambient conditions, and cut to 60 mm before use. All the chemicals used here were reagent grade and used without further purification.MethodsPretreatmentThe bamboo strips were firstly pretreated by soaking into 2 g/l H 2SO 4 solution with a strip to liquid ratio of 1:30 at 20±2o C for 24 h, followed by heating at 50o C for 1h,washed and vacuum-dried at 60o C for 8 h; then they were immersed into 100 g/l NaOH solution with a strip to liquid ratio of 1:20 at 20±2o C for 24 h, followed by heating at 60o C for 2 h, washed, and vacuum-dried at 60o C for 8 h.Chemical TreatmentAll the experiments were conducted on a high temperature laboratory dying machine (RY -1261, Shanghai Longling laboratory Instruments Co. Ltd., China). (1) Optimization of NaOH concentrationThe pretreated bamboo fibers were soaked into NaOH solution with different concentration (5, 10, 15, 20, 25, and 30 g/l ), with a fiber to liquid ratio of 1:10, at 90o C for 2 h.(2) Optimization of additives concentrationThe pretreated bamboo fibers were immersed into a mixed solution with NaOH at optimum concentration and the three additives, Na 5P 3O 10, Na 2SiO 3, and penetrating agent at different concentration, as shown in Table 1. The experiments were conducted with a fiber to liquid ratio of 1:10 at 90o C for 2 h.(3) Optimization of temperatureThe pretreated bamboo fibers were treated with NaOH and three additives with their optimum concentration at different temperature (80, 90, 100, 110, and 120o C), with a fiber to liquid ratio of 1:10 for 2 h.(4) Optimization of timeThe pretreated bamboo fibers were treated with NaOH and three additives with their optimum concentration, at optimum temperature, with a fiber to liquid ratio of 1:10 for different periods of time (1, 1.5, 2, 3, and 4 h).Determination of Fiber CharacteristicsFiber Chemical Composition, Characteristics , and Weight LossFiber chemical composition was determined according to the scheme of Soutar and Bryden [1,22] by successively removal of noncellulosic substances, that is, water solubles,wax, pectim, lignin, and hemicellulose. The content of cellulose was obtained by accounting for the amount of noncellulosic substances. Measurements were repeated at three times for each specimen.Fiber fineness in tex was determined as per standard methods [23] by dividing the mass of fibers by their known length [1]. The fineness was determined by averaging the experimental results of three specimens.Fiber average length was expressed as the length by weighted average. A textile fiber should have certain length to reach the requirement of textile processing, usually about 30 mm for cotton spinning machines. Therefore, only the fibers that are longer than 30 mm were counted in fiber length testing. Measurements were repeated at three timesfor each specimen.Figure 1. Strips of natural bamboo.Table 1. The concentration of three additives (g/l )Experimentalno.Na 5P 3O 10Na 2SO 3Penetrating agent 111221333154431453326353751385349552Modification of Natural Bamboo Fibers for Textile Applications Fibers and Polymers 2011, Vol.12, No.197Fiber mechanical properties were determined by a single fiber test conducted on a LLY-06 Tensile Tester (Laizhou Electronic Instrument Co. Ltd, Shandong Province, China) according to GB5886-1986, with clamps spaced at 100 mm and with test speed of 100 mm/min. The tenacity was obtained by averaging the experimental results of sixty fibers.Fiber weight loss was determined by the direct gravimetric method [1,24]. The average value was calculated for the three specimens tested.SEM, FTIR and X-ray AnalysisThe surface properties and FTIR spectra of original bamboo strips and optimally modified bamboo fiber were examined by scanning electron microscope (SEM) (JSM-5600LV, JEOL Ltd., Japan) and Fourier transform infrared spectrophotometer (FTIR) (NEXUS-670, Nicolet Company, US), respectively. FT-IR measurements were conducted at 20±2o C and 65±3 % RH.The crystal structure of bamboo strip and optimally modified fiber were obtained by using D/Max-2550 PC X-ray diffraction with Cu-Kα radiation (40 kV and 300 mA) operated at the scanning rate of 10o/min. X-ray diffraction measurements were also conducted at 20±2o C and 65±3% RH.Results and DiscussionCharacteristics of Pretreated Bamboo StripsA detailed investigation in terms of chemical composition and weight loss is carried out to determine the effects of pretreatment on bamboo strips. Table 2 shows the chemical composition of bamboo strips after different treatments. It can be found that the fraction of noncellulosic substances (56.59%) for the original bamboo strip is quite higher than other bast fibers, such as flax (about 20-30%) and hemp (about 22-33%) [25], implying that separating bamboo fibers for textile end uses is very difficult. After acid treatment and alkaline treatment, parts of noncellulosic substances are dissolved and removed, resulting in the increase of cellulosic fibrils from 43.41 to 46.83% and 50.23%, respectively. Table 2 also shows the increase of weight loss resulting from the removal of noncellulosic substances.As shown in Table 2, pretreatment with acid and alkaline seems to only have limited effects on the fibrillation of bamboo strips; however, it actually has essential influence on the modification of natural bamboo fibers. A very thin, but compact skin covering on the surface of bamboo stem can resist the penetration of alkaline solution, but it is easily degraded by H2SO4. Moreover, the acid and alkaline at quite high concentration can softly break off the compact connection between noncellulosic substances (mainly hemicellulose and lignin) and cellulosic fibrils at lower temperature, which can make NaOH solution easier to penetrate into fibers and so efficiently get rid of noncellulosic substances.Optimization of NaOH ConcentrationAlkali treatment can lead to fibrillation which causes the breaking down of the fiber bundle into smaller bundles so as to reduce fiber diameter [26]. Therefore, the pretreated bamboo strips are modified with NaOH solution. The NaOH concentration undoubtedly has important influence on the characteristics of bamboo fibers, as shown in Table 3 and Figure 2, respectively. The fraction of noncellulosic substances in bamboo fibers are gradually decreasing at increasing NaOH concentration from 5 to 25g/l, because the degradation of noncellulosic substances is enhanced with the increase ofTable 2. The chemical compositions and weight loss of differently treated bamboo stripsBamboo strip Hemicellulose (%)Lignin (%)Cellulose (%)Weight loss (%) Without treatment23.96 (2.3 %)a24.25 (2.6 %)43.41 (2.2 %)0 Acid treated22.79 (2.6 %)23.38 (2.4 %)46.83 (2.1 %) 7.3 (5.3 %) Alkaline treated21.85 (2.4 %)22.13 (2.3 %)50.23 (2.2 %)14.1 (4.1 %) a The value in the parenthesis is standard deviation.Table 3. The chemical compositions and weight loss of natural bamboo fibers treated by NaOHNaOH Hemicellulose (%)Lignin (%)Cellulose (%)Weight loss (%)5 g/l19.85 (2.5 %) a20.98 (2.4 %)55.48 (2.3 %)23.5 (3.5 %)10 g/l18.82 (2.8 %)18.87 (2.6 %)60.36 (2.1 %)31.6 (3.4 %)15 g/l15.95 (2.4 %)14.65 (2.1 %)67.75 (2.4 %)42.5 (3.0 %)20 g/l13.63 (3.1 %)13.09 (2.9 %)71.78 (2.2 %)48.1 (2.8 %)25 g/l13.49 (2.9 %)13.84 (3.2 %)71.31 (2.2 %)53.4 (3.3 %)30 g/l15.17 (2.7 %)15.14 (2.8 %)68.37 (2.1 %)64.7 (3.4 %) The value in the parenthesis is standard deviation.98Fibers and Polymers 2011, Vol.12, No.1Lifang Liu et al.NaOH concentration,which is also confirmed by the considerably increased weight loss in Table 3. The reduction of hemicellulose from 23.96 to 13.49% and lignin from 24.25 to 13.84% after treated with 25 g/l NaOH indicates that NaOH is quite effective to modify natural bamboo fibers. Kalia et al. [26] also reported that alkali treatment has the similar effect on flax fibers. Regarding the experimental result at 30g/l NaOH that shows a contrary trend, it is mainly due to the fact that although NaOH at high concentration can degrade more noncellulosic substances, it can also lead to the decomposition of cellulose. The result on weight loss in Table 3 also shows a remarkably increase at 30 g/l NaOH.Figure 2 shows the characteristics of natural bamboo fibers at increasing NaOH concentration in terms of linear density and tenacity. The liberation of fibers is increasing with the increase of NaOH concentration among 5-25g/l ;however, it reduces when NaOH concentration reaches to 30g/l . This phenomenon can be explained that NaOH atlower concentration can efficiently degrade hemicellulose and lignin that are situated between the cellulose regions to release smaller fiber bundles from the other parts of the strips, resulting in a decrease in fiber linear density; however at higher concentration NaOH can also decompose part of cellulose to cause the break of cellulosic fibrils and the destruction of structural integrity of bamboo fibers, resulting in an increase in fiber linear density. Moreover, NaOH at higher concentration can reduce the strength of fiber.Especially when NaOH reaches to 25g/l or above, the tenacity of fiber obviously decrease because of the damage of cellulosic fibrils, indicating that NaOH at too high concentration has no efforts devoted to the extraction of natural bamboo fibers. It can be concluded that an optimum results can be obtained using a 20g/l NaOH solution.Therefore, the following experiments for the optimization of additives concentration, treating time and temperature are all implemented with 20g/l NaOH.Optimization of Additives ConcentrationThe effects of three additives, that is, Na 5P 3O 10, Na 2SO 3,and penetrating agent on the characteristics of bamboo fibers are detailed in Table 4. It can be found that the addition of additives even at very low concentration can obviously decrease the linear density of fiber. As shown in Table 4, the linear density of modified fibers remarkably decreases from 6.25 tex to 4.64 tex even at 1 g/l of all the three additives. In addition, it can be observed that the influence of additives concentrations on the fiber linear density seems rather slight,but quite significant on the fiber tenacity, indicating the optimization of their concentration is necessary. The spinnability of a textile fiber is mainly determined by its fineness, length, and tenacity. As for the natural bamboo fiber in this study, the fineness is most important, because its length and tenacity can well satisfy the requirements for textile processing. Therefore, the concentration of three additives is optimized as 3 g/l Na 5P 3O 10, 5 g/l Na 2SO 3, and 3g/l penetrating agent. The bamboo fiber thus obtained hasFigure 2. The linear density and tenacity of bamboo fibers at increasing NaOH concentration.Table 4. The characteristics of fibers treated with additives at different concentrationExperimentalno.Na 5P 3O 10(g/l )Na 2SO 3(g/l )Penetrating agent(g/l )Experimental results a N t (tex)b P dt (cN·dtex -1)1112 4.64 (7.8 %) c 2.80 (6.5 %)2133 4.52 (7.5 %) 2.65 (7.2 %)3154 4.42 (6.4 %) 2.57 (7.7 %)4314 4.45 (7.1 %) 2.60 (5.6 %)5332 4.25 (6.9 %) 2.57 (6.1 %)6353 4.18 (7.5 %) 2.55 (7.5 %)7513 4.42 (5.3 %) 2.50 (6.6 %)8534 4.26 (6.2 %) 2.20 (8.1 %)9552 4.36 (5.8 %) 2.26 (7.8 %)a N tis fiber linear density and b P dt is fiber tenacity; c the value in the parenthesis is standard deviation.Modification of Natural Bamboo Fibers for Textile Applications Fibers and Polymers 2011, Vol.12, No.199fineness of 4.18 tex and tenacity of 2.55 cN/dtex.Optimization of Treating TemperatureTreating temperature is also an important parameterfor the modification of bamboo fibers, so experiments are carried out to optimize it. The experiment are implemented with 20 g/l NaOH, 3 g/l Na 5P 3O 10, 5 g/l Na 2SO 3, and 3 g/l penetrating agent. The characteristics of bamboo fibers at increasing treating temperature are illustrated in Figure 3. It is observed that the linear density is decreasing at 80~110o C, while showing a slight increase at 120o C; otherwise,the tenacity is reducing gradually. Higher temperature is contributed to the separation of cellulosic fibrils from noncellulosic substances by enhance the effect of treating agent; however, too high temperature should also be responsible for the decomposition of cellulosic fibrils,consequently resulting in the decrease in fiber linear density.It seems that the finest fiber can be achieved at 110o C;however, the corresponding fiber tenacity is extremely low,suggesting that the fiber is too weak to spin successfully.Therefore, the optimum treating temperature is determined as 100o C. The natural bamboo fiber thus obtained is 3.26 tex in fineness and 2.41 cN/dtex in tenacity.Optimization of Treating TimeThe penetration of alkaline solution into bamboo fibers strongly depends on the treating time. Longer treating time contributes to the modification; however, too longer time will lead to the decomposition of cellulose molecule and the obvious reduction in fiber tenacity. Therefore, detailed discussion is carried out in present study to obtain an optimum treating time. The experiment are implemented with 20 g/l NaOH, 3 g/l Na 5P 3O 10, 5 g/l Na 2SO 3, and 3 g/l penetrating agent at 100o C. As displayed in Figure 4, it can be found that the increase of treating time from 1 h to 2 hcontributes to the modification of bamboo fibers, but not when the time reaches to 3 or 4 h. Regarding fiber tenacity, it continually reduces with the increase of treating time. This is mainly because that more alkaline solution can penetrate into natural bamboo fibers and act on noncellulosic substances with increasing treating time, and so the linear density and tenacity of fibers undoubtedly reduces with the removal of hemicellulose and lignin that act as cement to connect cellulose region. However, the cellulosic fibrils will be degraded if being exposed to caustic solution for too long time (more than 2 h in this study), leading to a remarkable increase in fiber linear density and significant decrease in fiber tenacity. The treating time is optimized as 2 h by taking into account of fiber characteristics, energy loss, and production cost.In general, the optimum parameters for modification of natural bamboo fibers can be obtained as: 20 g/l NaOH, 3 g/l Na 5P 3O 10, 5 g/l Na 2SO 3, 3 g/l penetrating agent, with a fiber to liquid ratio of 1:10, at 100o C for 2 h. The fiber thus obtained has linear density of 3.26 tex and tenacity of 2.41cN/dtex.Microstructure Analysis on Optimally Treated Bamboo FiberThe main characteristics of the optimally treated bamboo fibers are investigated, as shown in Table 5. It can be found that the amount of cellulose component in bamboo fiber rises remarkably because of the removal of noncellulosic substances. The average length, breaking elongation, and modulus of natural bamboo fibers after different treatments were illustrated in Table 6. With the increase in treatment intensity, the average length and modulus decrease, but breaking elongation increases. This is also due to the removal of non-cellulosic substances that act as cementing material in natural bamboo fibers. However, as shown in Table 5,Figure 3. The effects of treating temperature on the characteristics of bamboo fibers.Figure 4. The effects of treating time on the characteristics of bamboo fibers.100Fibers and Polymers 2011, Vol.12, No.1Lifang Liu et al.high amount of hemicellulose and lignin that are 12.45 and 12.86%, respectively, still remain in optimally treated fiber, because of the considerable stable hemicellulose hydrogen bonding to cellulosic fibrils and the strong C-C linkages and other chemical groups in lignin [1].Figure 5 and Figure 6 are the surface pictures and cross-section pictures of bamboo strip and differently treated bamboo fibers, respectively. A large quantity of gum in theTable 5. The characteristics of optimally treated bamboo fiberLinear density (tex)Tenacity (cN/dtex)Hemicellulose (%)Lignin (%)Cellulose (%)3.26 (5.5 %)a 2.41 (7.3 %)12.45 (3.2 %)12.86 (2.9 %)73.25 (2.4 %) The value in the parenthesis is standard deviation.Table 6. The characteristics of differently treated bamboo fibersFiber Average length (mm)Breaking elongation (%)Modulus (GPa) Bamboo strip60 //Treated with 20 g/l NaOH53.7 (3.8 %) a 1.9 (8.8 %)23.8 (8.5 %)Treated with optimal additives48.1 (3.6 %) 2.5 (7.6 %)16.7 (8.7 %)Treated with optimal parameters44.5 (4.0 %) 2.8 (7.1 %)14.1 (8.1 %)aThe value in the parenthesis is standard deviation.Figure 5. Fracture surface (1500×) of (a) bamboo strip and bamboo fibers treated with (b) 20 g/l NaOH; (c) 20 g/l NaOH, 3 g/l Na5P3O10, 5g/l Na2SO3, and 3 g/l penetrating agent, and (d) optimal parameters.Modification of Natural Bamboo Fibers for Textile Applications Fibers and Polymers 2011, Vol.12, No.1101bamboo strip can be observed in Figure 5(a). After treatedwith 20 g/l NaOH, the bamboo fiber is fiberized, but still with large amount of impurities on surface (Figure 5(b)).With the increase in treatment intensity, the bamboo fibers are getting cleaner and finer (Figure 5(c) and (d), which is also supported by the pictures in Figure 6. As can be found in Figure 6(a),the natural bamboo fiber consists of numerous elementary fibers, and the elementary fiber has an irregular hollow polygonal cross-section. With the increase in treatment intensity (from Figure 6(a) to (b) and (d)), the number of elementary fibers is decreasing, meaning that the technical bamboo fiber is getting finer. Moreover, the inner structure of bamboo fiber becomes looser after treated with additive agents. As shown in Figure 6(c), clear cracks can be observed for thus produced natural bamboo fiber, indicating that the fiber can be easily separated into small bundles. FTIR spectra are also introduced here to illuminate the change in chemical compositions of natural bamboo fibersFigure 6. Cross-section of (a) bamboo strip (500×) and bamboo fibers treated with (b) 20 g/l NaOH (500×); (c) 20 g/l NaOH, 3 g/l Na 5P 3O 10,5 g/l Na 2SO 3, and 3 g/l penetrating agent (2000×), and (d) optimal parameters (500×).Figure 7. Partial FTIR spectra of natural bamboo fibers (a) without treatment and (b) after optimum treatment.102Fibers and Polymers 2011, Vol.12, No.1Lifang Liu et al.before and after treatment, as shown in Figure 7. The bandsappearance at about 1160, 1320, and 1370 cm -1 are characteristic for one of more possible positions of hemicellulose, and the bands at 1430 and 1640 cm -1 are for lignin, respectively. It can be observed that all the bands mentioned above are remarkable weaker for the fiber after treatment, indicating that a great amount of hemicellulose and lignin are removed from the fiber.Figure 8 shows the X-ray diffraction pattern for bamboo strips and optimally treated bamboo fiber. It found that they have the similar diffraction peaks, but with different intensity. Furthermore, their crystallinity degree are calculated by dividing the crystalline area by the total area formed by the curve in Figure 8, which are 67.5 and 70.3% for bamboo strip and optimally treated bamboo fiber, respectively.Swelling in NaOH introduces considerable changes in crystallinity of natural bamboo fiber, which is mainly due to the removal of the non-cellulosic material that leads to a better packing of cellulose chains [19].ConclusionNatural bamboo fibers were chemically extracted and modified in this paper, and the processing parameters were optimized to improve fiber quality. Reduced contents of noncellulosic substances and improved fiber fineness benefiting from the chemical modification can be observed from experimental results. The processing parameters are optimized as: 20g/l NaOH, 3g/l Na 5P 3O 10, 5g/l Na 2SO 3, 3g/l penetrating agent, with a fiber to liquid ratio of 1:10, at 100o C for 2h, and the natural bamboo fiber thus obtained has cellulose amount of 73.25%, fineness of 3.26tex,average length of 44.5 mm, breaking elongation of 2.8%and tenacity of 2.41 cN/dtex. The chemical modification in this study may offer a possibility of developing naturalbamboo fibers into practical applications in textiles.AcknowledgementsThe supports of the Fujian Provincial Science and Technology Agency (Project 2008HZ0001-3), National Natural Science Foundation of China (Project 50809016 and Project 10872048), and the Fundamental Research Funds for the Central Universities (Project 2009C01-1-01) are gratefully acknowledged. 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