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Syndiotactic 1,2-polybutadiene fibers produced by electrospinning
Materials Letters 61 (2007) 1319 – 1322 www.elsevier.com/locate/matlet
Syndiotactic 1,2-polybutadiene fibers produced by electrospinning Xiufeng Hao a,b , Xuequan Zhang a,⁎ a
Changchun Institute of Applied Chemistry Chinese Academy of Science, Changchun, 130022, PR China b Department of Polymer Science, Jilin University, Changchun, 130012, PR China Received 30 May 2006; accepted 6 July 2006 Available online 26 July 2006
Abstract Syndiotactic 1,2-polybutadiene (s-PB) is a typical thermoplastic elastomer with various applications because of its high reactivity. In the past, it is difficult to form s-PB fibers with a diameter below 10 μm because of the limitation of the conventional method such as melt spinning. Here, we report for the first time on the production of s-PB nanofibers by using a simple electrospinning method. Ultrafine s-PB fibers without beads were electrospun from s-PB solutions in dichloromethane and characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). At 4 wt.% concentration of s-PB, the average diameter of s-PB was about 130 nm. We found that dichloromethane was a unique suitable solvent for the electrospinning of s-PB fibers, and the structure of syndiotactic was changed through the electrospinning process. © 2006 Elsevier B.V. All rights reserved. Keywords: Electrospinning; Syndiotactic 1,2-polybutadiene; Nanofibers
1. Introduction Recently, researches have been focused on electrospinning because the preparation of ultrafine and uniform polymer fibers via electrospinning is an efficient processing method that overcomes the limitation of conventional fibers and non-woven mats [1–6], and electrospinning is a unique technique for the preparation of ultrafine polymer fibers with diameters in submicrometers or nanometers. These fibers with high specific surface area and porous structure lend themselves to a wide range of applications including filtration devices, membranes, optics, vascular grafts, protective clothing, molecular templates, tissue scaffolds and raw material for carbon fibers [7–13]. In this technique, a high electric field is generated between a polymer fluid contained in a glass syringe with a capillary tip and metallic collection screen. When the voltage reaches a critical value, the charge overcomes the surface tension of the deformed drop of the suspended polymer solution formed on the tip of the syringe, and a jet is produced. As the jet moves toward
⁎ Corresponding author. E-mail address: [email protected] (X. Zhang). 0167-577X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2006.07.022
the metal collector, the solvent evaporates and non-woven fibrous membranes are formed. A schematic diagram to interpret electrospinning of polymer results is shown in Fig. 1. So far, more than fifty different polymers have been successfully electrospun into ultrafine fibers with diameters ranging from b 3 nm to over 1 mm [14]. However, there is scarcely any literature related to electrospinning of any kinds of polybutadiene. As we know, materials with reduced dimensions can have properties significantly different from the bulk material. Syndiotactic 1,2-polybutadiene (s-PB) is an important thermoplastic elastomer with various applications because of its high reactivity. The melt spinning of s-PB was described by Ashitaka et al. [15,16] in previous articles. They found that the s-PBbased carbon fibers have good mechanical properties. But the fibers from conventional spinning method such as melt spinning have relatively thick fiber diameters of 10–20 μm, and it is difficult to form the melt of s-PB into filaments because of the sensitivity of s-PB to thermal degradation. In this study, we report for the first time on the production of s-PB nanofibers by using electrospinning method. The results were characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR),
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Fig. 1. The device for electrospinning.
Fig. 2. Electroprocessed structures from (a) 1 wt.%, (b) 2 wt.%, (c) 3 wt.%, (d) 4 wt.%, (e) 5 wt.%, and (f) 6 wt.% s-PB in dichloromethane.
X. Hao, X. Zhang / Materials Letters 61 (2007) 1319–1322
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by Fourier transform infrared spectroscopy (FTIR) (Bruker Vertex 70, USA). X-ray diffraction of the fibers was performed at room temperature using a diffractometer (Philips, PW1710 based). 2.3. Spinning solution preparation To electrospin s-PB fibers, s-PB/dichloromethane (CH2Cl2) (1 wt.%–6 wt.%) solutions were prepared, and s-PB solutions in a common solvent, such as carbon tetrachloride (CCl4), carbon disulfide (CS2), and chloroform (CHCl3) were also prepared. All these solutions were stirred for 24 h at room temperature for electrospinning. Fig. 3. A porous half spheres structure from 1 wt.% s-PB in dichloromethane.
and X-ray diffraction (XRD) in order to find the fundamental characteristics of s-PB fibers. 2. Experimental
2.4. Electrospinning process The s-PB solution was held in a spinning nozzle with a tip diameter of 1 mm, which was as an anode with a certain distance from cathode. An aluminum foil was stuck on the cathode to collect s-PB fibers at 11 kV voltage and 15 cm working distance.
2.1. Materials 3. Results and discussion
All reagents were used without further purification. Syndiotactic 1,2-polybutadiene (s-PB) was obtained from Japan Synthetic Rubber Co., Ltd. All solvents were purchased from Beijing Beihua Fine Chemicals Co., Ltd. 2.2. Instruments The s-PB solutions were electrospun by using an electrospinning apparatus equipped with power supply (ZH-10, Datone Co., China). Electrospun fiber diameter and morphology were analyzed using an environmental scanning electron microscope (ESEM) (XL30, USA). Their chemical composition was verified
3.1. Morphology Most of the solvents have poor fiber-formation ability for s-PB except CH2Cl2. The SEM images (Fig. 2) show evolution in morphology of the microstructures with different s-PB concentration in s-PB/CH2Cl2 solutions. It can be seen that with the increment in the concentration of the s-PB solution, and the results are changed from spheres to fibers. That is, at 1 wt.% of s-PB, a porous half sphere structure with a diameter of about 15 μm was observed (Fig. 3). The diameter of the pore in spheres is under 100 nm. At 2–3 wt.%, the morphology is fiber-beads. The smooth fiber is formed when the s-PB concentration is above 4 wt.%. At 4 wt.%, the diameter of the s-PB
Fig. 4. IR spectra of the raw material of s-PB (a) and the electrospun s-PB fibers (b).
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Fig. 5. XRD patterns of the raw material of s-PB (a) and the electrospun s-PB fibers (b).
fibers ranged from 90 nm to 190 nm, with an average fiber diameter of 130 nm. 4 wt.% is the best concentration for attaining nanofibers with the thinnest diameter compared to those at other weight concentrations.
about 130 nm. The structure of syndiotactic is not changed in the electrospinning process and the results have the same lattice structure as the raw materials.
3.2. IR and XRD analyses
References
In order to examine whether the structure of s-PB is changed in the electrospinning process, IR spectra and XRD of both the raw material of s-PB and the electrospun s-PB were measured. Fig. 4 shows the IR spectra of the raw material (a) and electrospun fibers (b). Both of them have an absorption band at 990 cm− 1 and 664 cm− 1, which is the syndiotactic characteristic absorption band of s-PB. It is concluded that the electrospinning process doesn't affect the structure of s-PB. Fig. 5 shows the X-ray diffraction patterns of raw material of s-PB (a) and electrospun s-PB fibers (b). Diffraction angles, 2θ at the maximum intensity of electrospun s-PB fibers, correspond to spacings of 6.67, 5.51, 4.22 and 3.81 Å, respectively, and the structure of a unit cell is estimated to be orthorhombic. The values are almost identical with those of raw materials and literature [17]. Such agreement leads to the conclusion that the results have the same lattice structure as the raw materials.
4. Conclusions Syndiotactic 1,2-polybutadiene (s-PB) nanofibers have been successfully prepared by the electrospinning method. We find that dichloromethane is a unique suitable solvent for the electrospinning of s-PB fibers. With the increment in the concentration of the s-PB solution, the results are changed from spheres to fibers. At 4 wt.%, the average diameter of s-PB is
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]
M.M. Berghoef, J.G. Vansco, Adv. Mater. 11 (1999) 1362. H. Fong, D.H. Reneker, J. Polym. Sci., Part B 37 (1999) 3488. H. Fong, L. Weidong, C.S. Wang, R.A. Vaia, Polymer 43 (2002) 775. L. Huang, A. McMillan, R.P. Apkarian, B. Pourdeyhimi, V.P. Conticello, Chaik of EL, Macromolecules 33 (2000) 2989. M. Bognitzki, H. Hou, M. Ishaque, T. Frese, M. Hellweg, C. Schwarte, A. Schaper, J.H. Wendorff, A. Greiner, Adv. Mater. 12 (2000) 637. C.J. Buchko, L.C. Chen, Y. Shen, D.C. Martin, Polymer 40 (1999) 7397. T. Grafe, K. Graham, Nonwoven Technol. Rev. (2003) 51. E.-R. Kenawy, J.M. Layman, J.R. Watkins, G.L. Bowlin, J.A. Matthews, D.G. Simpson, G.E. Wnek, Biomaterials 24 (2003) 907. J.A. Matthews, G.W. Wnek, D.G. Simpson, G.L. Bowlin, Biomacromolecules 3 (2002) 232. Sang Hee Park, Chan Kim, Young Ok Choi, Kap Seung Yang, Carbon 41 (2003) 2655. Sang Hee Park, Chan Kim, Kap Seung Yang, Synth. Met. 143 (2004) 175. I. Chun, D.H. Reneker, H. Fong, et al., Adv. Mater. 31 (1999) 36. X. Lu, Y. Zhao, C. Wang, Adv. Mater. 17 (2005) 2485. Zheng-Ming Huang, Y.-Z. Zhang, Compos. Sci. Technol. 63 (2003) 2223. Hidetomo Ashitaka, Yoshihiro Kusuki, Shuji Yamamoto, Yoshiaki Ogata, Akira Nagasaka, J. Appl. Polym. Sci. 29 (1984) 2763. Hidetomo Ashitaka, Yoshihiro Kusuki, Yukihiko Asano, Shuji Yamamoto, Haruo Ueno, Akira Nagasaka, J. Polym. Sci., Polym. Chem. Ed. 21 (1983) 1111. G. Natta, P. Corradini, Ibid 20 (1956) 251.
Syndiotactic 1,2-polybutadiene fibers produced by electrospinning Xiufeng Hao a,b , Xuequan Zhang a,⁎ a
Changchun Institute of Applied Chemistry Chinese Academy of Science, Changchun, 130022, PR China b Department of Polymer Science, Jilin University, Changchun, 130012, PR China Received 30 May 2006; accepted 6 July 2006 Available online 26 July 2006
Abstract Syndiotactic 1,2-polybutadiene (s-PB) is a typical thermoplastic elastomer with various applications because of its high reactivity. In the past, it is difficult to form s-PB fibers with a diameter below 10 μm because of the limitation of the conventional method such as melt spinning. Here, we report for the first time on the production of s-PB nanofibers by using a simple electrospinning method. Ultrafine s-PB fibers without beads were electrospun from s-PB solutions in dichloromethane and characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). At 4 wt.% concentration of s-PB, the average diameter of s-PB was about 130 nm. We found that dichloromethane was a unique suitable solvent for the electrospinning of s-PB fibers, and the structure of syndiotactic was changed through the electrospinning process. © 2006 Elsevier B.V. All rights reserved. Keywords: Electrospinning; Syndiotactic 1,2-polybutadiene; Nanofibers
1. Introduction Recently, researches have been focused on electrospinning because the preparation of ultrafine and uniform polymer fibers via electrospinning is an efficient processing method that overcomes the limitation of conventional fibers and non-woven mats [1–6], and electrospinning is a unique technique for the preparation of ultrafine polymer fibers with diameters in submicrometers or nanometers. These fibers with high specific surface area and porous structure lend themselves to a wide range of applications including filtration devices, membranes, optics, vascular grafts, protective clothing, molecular templates, tissue scaffolds and raw material for carbon fibers [7–13]. In this technique, a high electric field is generated between a polymer fluid contained in a glass syringe with a capillary tip and metallic collection screen. When the voltage reaches a critical value, the charge overcomes the surface tension of the deformed drop of the suspended polymer solution formed on the tip of the syringe, and a jet is produced. As the jet moves toward
⁎ Corresponding author. E-mail address: [email protected] (X. Zhang). 0167-577X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2006.07.022
the metal collector, the solvent evaporates and non-woven fibrous membranes are formed. A schematic diagram to interpret electrospinning of polymer results is shown in Fig. 1. So far, more than fifty different polymers have been successfully electrospun into ultrafine fibers with diameters ranging from b 3 nm to over 1 mm [14]. However, there is scarcely any literature related to electrospinning of any kinds of polybutadiene. As we know, materials with reduced dimensions can have properties significantly different from the bulk material. Syndiotactic 1,2-polybutadiene (s-PB) is an important thermoplastic elastomer with various applications because of its high reactivity. The melt spinning of s-PB was described by Ashitaka et al. [15,16] in previous articles. They found that the s-PBbased carbon fibers have good mechanical properties. But the fibers from conventional spinning method such as melt spinning have relatively thick fiber diameters of 10–20 μm, and it is difficult to form the melt of s-PB into filaments because of the sensitivity of s-PB to thermal degradation. In this study, we report for the first time on the production of s-PB nanofibers by using electrospinning method. The results were characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR),
1320
X. Hao, X. Zhang / Materials Letters 61 (2007) 1319–1322
Fig. 1. The device for electrospinning.
Fig. 2. Electroprocessed structures from (a) 1 wt.%, (b) 2 wt.%, (c) 3 wt.%, (d) 4 wt.%, (e) 5 wt.%, and (f) 6 wt.% s-PB in dichloromethane.
X. Hao, X. Zhang / Materials Letters 61 (2007) 1319–1322
1321
by Fourier transform infrared spectroscopy (FTIR) (Bruker Vertex 70, USA). X-ray diffraction of the fibers was performed at room temperature using a diffractometer (Philips, PW1710 based). 2.3. Spinning solution preparation To electrospin s-PB fibers, s-PB/dichloromethane (CH2Cl2) (1 wt.%–6 wt.%) solutions were prepared, and s-PB solutions in a common solvent, such as carbon tetrachloride (CCl4), carbon disulfide (CS2), and chloroform (CHCl3) were also prepared. All these solutions were stirred for 24 h at room temperature for electrospinning. Fig. 3. A porous half spheres structure from 1 wt.% s-PB in dichloromethane.
and X-ray diffraction (XRD) in order to find the fundamental characteristics of s-PB fibers. 2. Experimental
2.4. Electrospinning process The s-PB solution was held in a spinning nozzle with a tip diameter of 1 mm, which was as an anode with a certain distance from cathode. An aluminum foil was stuck on the cathode to collect s-PB fibers at 11 kV voltage and 15 cm working distance.
2.1. Materials 3. Results and discussion
All reagents were used without further purification. Syndiotactic 1,2-polybutadiene (s-PB) was obtained from Japan Synthetic Rubber Co., Ltd. All solvents were purchased from Beijing Beihua Fine Chemicals Co., Ltd. 2.2. Instruments The s-PB solutions were electrospun by using an electrospinning apparatus equipped with power supply (ZH-10, Datone Co., China). Electrospun fiber diameter and morphology were analyzed using an environmental scanning electron microscope (ESEM) (XL30, USA). Their chemical composition was verified
3.1. Morphology Most of the solvents have poor fiber-formation ability for s-PB except CH2Cl2. The SEM images (Fig. 2) show evolution in morphology of the microstructures with different s-PB concentration in s-PB/CH2Cl2 solutions. It can be seen that with the increment in the concentration of the s-PB solution, and the results are changed from spheres to fibers. That is, at 1 wt.% of s-PB, a porous half sphere structure with a diameter of about 15 μm was observed (Fig. 3). The diameter of the pore in spheres is under 100 nm. At 2–3 wt.%, the morphology is fiber-beads. The smooth fiber is formed when the s-PB concentration is above 4 wt.%. At 4 wt.%, the diameter of the s-PB
Fig. 4. IR spectra of the raw material of s-PB (a) and the electrospun s-PB fibers (b).
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X. Hao, X. Zhang / Materials Letters 61 (2007) 1319–1322
Fig. 5. XRD patterns of the raw material of s-PB (a) and the electrospun s-PB fibers (b).
fibers ranged from 90 nm to 190 nm, with an average fiber diameter of 130 nm. 4 wt.% is the best concentration for attaining nanofibers with the thinnest diameter compared to those at other weight concentrations.
about 130 nm. The structure of syndiotactic is not changed in the electrospinning process and the results have the same lattice structure as the raw materials.
3.2. IR and XRD analyses
References
In order to examine whether the structure of s-PB is changed in the electrospinning process, IR spectra and XRD of both the raw material of s-PB and the electrospun s-PB were measured. Fig. 4 shows the IR spectra of the raw material (a) and electrospun fibers (b). Both of them have an absorption band at 990 cm− 1 and 664 cm− 1, which is the syndiotactic characteristic absorption band of s-PB. It is concluded that the electrospinning process doesn't affect the structure of s-PB. Fig. 5 shows the X-ray diffraction patterns of raw material of s-PB (a) and electrospun s-PB fibers (b). Diffraction angles, 2θ at the maximum intensity of electrospun s-PB fibers, correspond to spacings of 6.67, 5.51, 4.22 and 3.81 Å, respectively, and the structure of a unit cell is estimated to be orthorhombic. The values are almost identical with those of raw materials and literature [17]. Such agreement leads to the conclusion that the results have the same lattice structure as the raw materials.
4. Conclusions Syndiotactic 1,2-polybutadiene (s-PB) nanofibers have been successfully prepared by the electrospinning method. We find that dichloromethane is a unique suitable solvent for the electrospinning of s-PB fibers. With the increment in the concentration of the s-PB solution, the results are changed from spheres to fibers. At 4 wt.%, the average diameter of s-PB is
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17]
M.M. Berghoef, J.G. Vansco, Adv. Mater. 11 (1999) 1362. H. Fong, D.H. Reneker, J. Polym. Sci., Part B 37 (1999) 3488. H. Fong, L. Weidong, C.S. Wang, R.A. Vaia, Polymer 43 (2002) 775. L. Huang, A. McMillan, R.P. Apkarian, B. Pourdeyhimi, V.P. Conticello, Chaik of EL, Macromolecules 33 (2000) 2989. M. Bognitzki, H. Hou, M. Ishaque, T. Frese, M. Hellweg, C. Schwarte, A. Schaper, J.H. Wendorff, A. Greiner, Adv. Mater. 12 (2000) 637. C.J. Buchko, L.C. Chen, Y. Shen, D.C. Martin, Polymer 40 (1999) 7397. T. Grafe, K. Graham, Nonwoven Technol. Rev. (2003) 51. E.-R. Kenawy, J.M. Layman, J.R. Watkins, G.L. Bowlin, J.A. Matthews, D.G. Simpson, G.E. Wnek, Biomaterials 24 (2003) 907. J.A. Matthews, G.W. Wnek, D.G. Simpson, G.L. Bowlin, Biomacromolecules 3 (2002) 232. Sang Hee Park, Chan Kim, Young Ok Choi, Kap Seung Yang, Carbon 41 (2003) 2655. Sang Hee Park, Chan Kim, Kap Seung Yang, Synth. Met. 143 (2004) 175. I. Chun, D.H. Reneker, H. Fong, et al., Adv. Mater. 31 (1999) 36. X. Lu, Y. Zhao, C. Wang, Adv. Mater. 17 (2005) 2485. Zheng-Ming Huang, Y.-Z. Zhang, Compos. Sci. Technol. 63 (2003) 2223. Hidetomo Ashitaka, Yoshihiro Kusuki, Shuji Yamamoto, Yoshiaki Ogata, Akira Nagasaka, J. Appl. Polym. Sci. 29 (1984) 2763. Hidetomo Ashitaka, Yoshihiro Kusuki, Yukihiko Asano, Shuji Yamamoto, Haruo Ueno, Akira Nagasaka, J. Polym. Sci., Polym. Chem. Ed. 21 (1983) 1111. G. Natta, P. Corradini, Ibid 20 (1956) 251.