聚羥基丁酸酯(PHB)為一生物可分解性材料，具有生物相容性，可應用於生醫材料方面，將其製成纖維膜，可使應用範圍更為廣泛。聚羥基丁酸酯(PHB)纖維可藉由PHB溶於溶劑後，經由電紡絲製備而得。但在PHB/Chloroform系統中，因為溶劑沸點低，以固定流量流出針頭後，突出針頭前端之液滴即快速揮發，造成針頭前端阻塞使製程無法連續。本研究則利用氮氣導引飽和溶劑蒸氣至針端，改善阻塞的問題。

　　本研究將PHB溶入Chloroform/DMF的共溶劑中，改變PHB溶液濃度，探討纖維直徑和形態的變化。液柱直徑為決定纖維直徑之重要因子，發現液柱直徑會隨著濃度降低而降低。藉由高速攝影機，可觀察到液柱在bending instability區域的情形。以共溶劑之系統，當溶液濃度為1wt%時，bending instability區域呈現顆粒狀態；濃度為3wt%時，呈現beaded jet狀態；濃度為5wt%時，呈現smooth jet狀態。以共溶劑之系統，當溶液濃度為5wt%時，製備出平均直徑為1.76±0.33m；濃度為3wt%時，平均直徑為618±137nm；濃度為1wt%時，平均直徑為156±69nm。

　Polyhydroxybutyrate(PHB) is a biodegradable material that has attracted enormous attention in agricultural, pharmaceutical and medical industry due to its biocompatibility and biodegradability. PHB fibers were electrospun from solution. In the PHB/Chloroform system where the solvent used has a low boiling point, the pendent drop at the tip of the needle will dry out very quickly, and block the tip, making the collection process discontinuous or even impossible to carry out. In this experiment, a coaxial gas jacket was used to guide the saturated vapor to surround the Taylor cone during electrospinning process. This design can stabilize the cone-jet formation.

　In this study PHB was dissolved in the mixture of chloroform and DMF. We discuss the varieties of fiber diameter and morphology when the processing variables, such as the concentration、flowrate、voltage and working distance are changed. The jet diameter is the determining factor for the fiber diameter. The most important factor affecting the jet diameter is concentration. The jet diameter and fiber diameter decrease when the concentration is decreased. The bending instability region is observed by high speed camera. In the PHB/Chloroform=90/10 system, the jet morphology in bending instability region is droplet when concentration is 1wt%, beaded jet for 3wt% solutions, and smooth jet for 5wt% solutions.The average diameter of electrospun fibers was 1.76 0.33m for 5wt% solutions, 618 137nm for 3wt% solutions, and 156 69nm for 1wt% solutions.

八、參考文獻

【1】G. Griffin, “Chemistry and technology of biodegradable polymers”, Chapman and Hall, London, p48-96 (1994)。
【2】吳文娟，“ 有機資源再利用及生物可分解塑膠 ”，飼料工業季刊，第56期，p24-41。
【3】Prepared in association with ExcelPlas Australia, “Biodegradable Plastics-Developments and Environmental Impacts”, October, 2002
【4】M. Lemoigne, Ann. Inst. Past. , 34, 144(1925)
【5】J. Hao, X. Deng, “Semi-interpenetrating networks of bacterial poly(3-hydroxybutyrate) with net-poly(ethylene glycol)” Polymer, 42, 4091 (2001)
【6】黃怡菁， “生物可分解材料澱粉與PHB(poly-3- hydroxy butyrate) 合膠之製備及性質研究”，中國文化大學材料科學與製造研究所碩士論文。(2004)
【7】S. Randriamahefa, E. Renard, P. Guérin, V. Langlois, “Fourier transform infrared spectroscopy for screening and quantifying production of PHAs by pseudomonas grown on sodium octanoate” Biomacromolecules, 4, 1092 (2003)
【8】L.M.W.K. Gunaratne, R. A. Shanks, G. Amarasinghe, “Thermal historyeffects on crystallization and melting of poly(3-hydroxybutyrate)” Thermochimica Acta, 423,127 (2004)
【9】A. Steinbüchel, B. Füchtenbusch, “Bacterial and other biological systems for polyester production” , Trends Biol. Technol. , 16, 419 (1998)
【10】T. Ikejima, Y. Inoue, “Crystallization behavior and environmental biodegradability of the blend films of poly(3-hydroxybutyric acid) with chitin and chitosan” Carbohydrate polymers, 41, 351(2000)
【11】H. Sato, R. Murakami, A. Padermshoke, F. Hirose, K. Senda, I. Noda, Y. Ozaki, “Infrared spectroscopy studies of CH…O hydrogen bondings and thermal behavior of biodegradable poly(hydroxyalkanoate)” Macromolecules, 37, 7203 (2004)
【12】J. Zeleny, J. Phys. Pev. 3, 69 (1914)
【13】A. Formhals, US patent No. 1975504 (1934)
【14】D. H. Reneker, I. Chun, “Nanometer diameter fibres of polymer, produced by electrospinning”, Nanotechnology ,7, 216(1996)。
【15】H. Fong, I. Chun, D. H. Reneker, “Beaded nanofibers formed during electrospinning” , Polymer, 40, 4585 (1999)
【16】G. I. Taylor, “Disintegration of water drops in an electric field”, Proc. R. Soc. London, Ser. A 280, 383(1964)
【17】M. Cloupeau, B. Prunet-Foch, “Electrostatic spraying of liquids in cone-jet mode”J. Electrostatics, 22, 135, (1989)。
【18】J. Doshi, Ph. D. Dissertation, University of Akron, 1997; pp102-116.
【19】H. Xu, D. Galehouse, D.H. Reneker, “Study of the relationship between jet diameter and interference color during electrospinning”, Polymer Materials: Science & Engineering, 88, 37(2003).
【20】Y. M. Shin, M. M. Hohman, M. P. Brenner, G. C. Rutledge, “Experimental characterization of electrospinning: the electrically forced jet and instabilities”, Polymer, 42, 9955 (2001).
【21】P. K. Baumgartyen, “Electrostatic spinning of acrylic microfibers”, J. Colloid Interface Sci. 36, 71(1971).
【22】D. H. Reneker, A. L. Yarin, H. Fong, S. Koombhongse, “Bending instability of electrospinning of nanofibers”, J. Appl. Phys., 87, 4531, (2000)。
【23】H. Liu, Y. L. Hsieh, “Ultrafine fibros cellulose membranes from electrospinning of cellulose acetate” J. Polym. Sci., Part:B, Polym. Phys. , 40, 2119(2001).
【24】X. Zong, K. Kim, D. Fang, S. Ran, B. S. Hsiao, B. Chu, “Structure and process relationship of electrospun bioabsorbable nanofiber membranes”, Polymer, 43, 4403 (2002)
【25】K. H. Lee, H. Y. Kim, H. J. Bang, Y. H. Jung, S. G. Lee, “The change of bead morphology formed on electrospun polystyrene fibers”, Polymer, 44, 4029 (2003)
【26】K. H. Lee, H. Y. Kim, Y. J. Ryu, K. W. Kim, S. W. Choi, “Mechanical behavior of electrospun fiber mats of poly(vinyl chloride)/polyurethane polyblends”, J. Polym. Sci., Part:B, Polym. Phys. , 41, 1256 (2003)
【27】D. Li, Y. Xia, “Fabrication of titania nanofibers by electrospinning” Nano Letters, 3, 555(2003)
【28】J. M. Deitzel, J. Kleinmeyer, D. Harris, N. C. B. Tan, “The effect of processing variables on the morphology of electrospun nanofibers and textiles”, Polymer, 42, 261 (2001)
【29】T. Lin, H. Wang, H. Wang, X. Wang, “The charge effect of cationic surfactants on the elimination of fiber beads in the electrospinning of polystyrene” Nanotechnology, 15, 1375 (2004)
【30】A. Koski, K. Yim, S. Shivkumar, “Effect of molecular weight on fibrous PVA produced by electrospinning”, Materials Letters, 58, 493 (2004)
【31】C. L. Casper, J. S. Stephens, N. G. Tassi, D. B. Chase, J. F. Rabolt, “Controlling surface morphology of electrospun polystyrene fibers:effect of humidity and molecular weight in the electrospinning process”, Macromolecules 37, 573(2004).
【32】S. Koombhongse, W. Liu, D.H. Reneker, “Flat polymer ribbons and other shapes by electrospinning” J. Polym. Sci.,Part:B, Polym. Phys. 39, 2598(2001).
【33】M. Bognitzki, W.Czado, T. Frese, A. Schapor, M. Hellwig, M.Steinhart, A. Greiner, J. H. Wendorff, “Nanostructured fibers via electrospinning”, Adv. Mater. 13, 70 (2001)
【34】S. Megelski, J. S. Stephens, D. B. Chase, J. F. Rabolt, “Micro- and nanostructured surface morphology on electrospun polymer fibers” , Macromolecules 35, 8456 (2002)
【35】L. Wannatong, A. Sirivat, P. Supaphol, “Effects of solvents on electrospun polymeric fibers:preliminary study on polystyrene” Polym. Int. 53, 1851(2004)

【36】C. J. Buchko, L. C. Chen, Y. Shen, D. C. Martin, “Processing and microstructural characterization of porous biocompatible protein polymer thin films” Polymer, 40, 7397(1999)
【37】K. H. Lee, H. Y. Kim, Y. M. La, D. R. Lee, N. H. Sung, “Influence of a mixing solvent with tetrahydrofuran and n,n-dimethylformamide on electrospun poly(vinyl chloride) nonwoven mats”, J. Polym. Sci. , Part : B, Polym. Phys. 40, 2259(2002)
【38】G. Larsen, R. Spretz, R. Velarde-Ortiz, “Use of coaxial gas jackets to stabilize Taylor Cone of volatile solutions and to induce particle-to-fiber transitions”, Adv. Mater. 16, 166 (2004)
【39】B. M. Min, S.W. Lee, J. N. Lim, Y.You, T. s. Lee, P. H. Kang, W. H. Park, “Chitin and chitosan nanofibers: electrospinning of chitin and deacetylation of chitin nanofibers” Polymer, 45, 7137(2004)
【40】K. Ohkawa, D. Cha, H. Kim, A. Nishida, H. Yamamoto, “Electrospinning of chitosan” Macromolecular Rapid Communications, 25, 1600 (2004)
【41】B. Duan, C. Dong, X. Yuan, K.Yao, “Electrospinning of chitosan solutions in acetic acid with poly(ethylene oxide)” J. Biomater. Sci. Polymer Edn, 15, 6, 797 (2004)
【42】J. A. Matthews, G. E. Wnek, D. G. Simpson, G. L. Bowin, “Electrospinning of collagen nanofibers” Biomacromolecules, 3, 232 (2002)
【43】L. Huang, R. P. Apkarian, E. L. Chaikof, Scanning, 23, 372(2001)
【44】L. Huang, K. Nagapudi, R. P. Apkarian, E. L. Chaikof, “Engineered collagen-PEO nanofibers and fabrics”, J. Biomater. Sci. Polymer Edn, 12, 979(2001)
【45】E. R. Kenawy, G. L. Bowlin, K. Mansfield, J. Layman, D. G. Simpson, E. H. Sanders, G. E. Wnek, “Release of tetracycline hydrochloride from electrospun poly(ethylene-co-vinylacetate), poly(lactic acid), and a blend”, J. of Controlled Release, 81, 57(2002)
【46】J. S. Choia, S. W. Leea, L. Jeonga, S. H. Baeb, B. C. Minb,
J. H. Youkc, W. H. Parka, “Effect of organosoluble salts on the nanofibrous structure of electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate)” International Journal of Biological Macromolecules, 34, 249 (2004)
【47】Z. M. Huang, Y. Z. Zhang, M. Kotaki, S. Ramakrishna, “A review on polymer nanofibers by electrospinning and their applications in nanocomposites” Compos. Sci. Technol. 63, 2223(2003).
【48】E. D. Boland, G. E. Wnek, D. G. Simpson, K. J. Pawlowski, G. L. Bowlin, “Tailoring tissue engineering scaffolds using electrostatic processing techniques:A study of poly(Glycolic acid) electrospinning” J. Macromol. Sci.—Pure Apply. Chem., A38, 12, 1231(2001)
【49】E. Zussman, A. Theron, A. L. Yarin, “Formation of nanofibers crossbars in electrospinning”, Appl. Phys. Lett. 82, 973(2003)
【50】A. Theron, E. Zussman, A.L. Tarin, “Electrostatic fileld-assisted alignment of electrospun nanofibres”, Nanotechnology 12, 384(2001).
【51】E. Smita, U. Bu˝ttnerb, R. D. Sanderson, “Continuous yarns from electrospun fibers”, Polymer, 46, 2419 (2005)
【52】R. Dersch, T. Liu, A. K. Schaper, A. Greiner, J. H. Wendorff, “Electrospun nanofibers: Internal structure and intrinsic
orientation” Journal of Polymer Science: Part A: Polymer Chemistry, 41, 545 (2003)
【53】P. Katta, M. Alessandro, R. D. Ramsier, and G. G. Chase, “Continuous electrospinning of aligned polymer nanofibers onto a wire drum Collector” Nano Lett., 4, (2004)
【54】J. M. Deitzel, J. D. Kleinmeyer, J. K. Hirvonen, N. C. Beck Tan, “Controlled deposition of electrospun poly(ethylene oxide) fibers” Polymer, 42, 8163 (2001)
【55】P. D. Daltona, D. Klee, Martin Möller “Electrospinning with dual collection rings” Polymer , 46 ,611 (2005)
【56】M. Vert , S. Li , H. Garreau, “New insights on the degradation of bioresorbable polymeric devices based on lactic and glycolic acids”, Clin Mater., 10,3 (1992)
【57】V. Chemie, “Lactic acid: Properties and Chemistry of Lactic acid and Derivatives”, pp.221, 1971.
【58】S. A. Angadjivand, M. G. Schwartz, P. D. Eitzman, M. E. Jones. US patent, 6,375,886(2002)
【59】楊炎橙，“以電氣紡絲製備具有奈米結構之生物分解性薄膜”，台北醫學大學口腔醫學院，口腔復健醫學研究所碩士論文。(2004)
【60】F. A. Jenkins and H. E. White (1976). Fundamentals of Optics, Fourth Edition, P316~322。
【61】R. Serway, Principles of Physics, 3rd Ed.
【62】R. Russo, “An alternative method for the determination of the birefringence in stretched polymeric films”, Polym. Testing 20, 283, (2001).
【63】L. L. Zhang, S. H. Goh, S.Y. Lee, G. R. Hee, “Miscibility, melting and crystallization behavior of two bacterial polyester/poly(epichlorohydrin-co-ethylene oxide) blend systems” Polymer, 41, 1429 (2000)
【64】林健樺, “以電紡絲製備聚苯乙烯纖維膜”, 成功大學化工碩士論文, (2004)
【65】H. Sato, R. Murakami, A. Padermshoke, F. Hirose, K. Senda, I. Noda, Y. Ozaki, “Infrared spectroscopy studies of CH…O hydrogen bondings and thermal behavior of biodegradable poly(hydroxyalkanoate)”Macromolecules, 37, 7203 (2004)
【66】L. P. Razumovskii, A. L. Iordanskii, G. E. Zaikov, “Sorption and diffusion of water and organic solvents in poly(β-hydroxybutyrate) films”Polymer degradation and stability, 44, 171(1994)