本研究分別以兩種不同方法配製聚乙烯醇(PVA)水溶液，第一種為在室溫下將PVA粉末與去離子水混合並在90 oC的油浴槽中攪拌1.5小時，稱此為庭宇法；另一種為承瑋法，將PVA與90 oC的去離子水混合並在90 oC的油浴槽中攪拌4小時。以庭宇法與承瑋法所得7 wt.%水溶液在25 oC下的黏度分別為370與680 cP。同為承瑋法所得，7與9 wt.%溶液的黏度分別為680與2180 cP。

以高速攝影機分別觀察兩種方式下所得7與9 wt.%水溶液的電紡液柱隨時間的變化，發現均有看似斷掉的行為發生，且在相同濃度下承瑋法所得電紡液柱發生此現象的頻率為庭宇法的60倍。觀察並計算電紡庭宇法所得7 wt.%液柱長度隨時間的變化、波的縱向及橫向速度，來了解電紡液柱在whipping區間的甩動行為。

利用乾玻片收集液柱，觀察到少量液柱內部具有方向性結構，此類液柱表面高低起伏程度比沒有方向性結構的液柱小。以含有非溶劑正丙醇的不同類型玻片收集液柱，發現其表面有一層具方向性的微結構，液柱內部有線狀與顆粒狀結構存在，且表面存在nodular結構。

以AFM觀察電紡以庭宇法配製7 wt%溶液所得纖維，發現表面有間距0.98 nm的規則鋸齒狀結構。以超音波震盪後發現纖維的斷裂處有necked結構，推測此為液柱內因相分離產生的結構。
以超音波震盪含有PVA電紡纖維膜的正丙醇溶液，在低功率下所得結果具有較好的分散性。再緩慢倒入iPP粉末以製備複材。利用OM及DSC觀察複材的動態結晶行為，發現PVA纖維不能誘導台塑iPP產生穿晶。

In this study, polyvinyl alcohol (PVA) aqueous solution was prepared in two different ways. The first way, Ting-Yu’s method, is to mix the PVA powder with deionized water at room temperature and stir for 1.5 hours in oil bath at 90 oC. The other way, Cheng-Wei’s method, is that PVA mixed with 90 oC distilled water and stirring at 90 °C for 4 hours. The viscosities of 7 wt.% aqueous solutions which were prepared by Ting-Yu’s and Cheng-Wei’s method at 25 oC are 370 and 680 cP, respectively. The viscosities of 7 and 9 wt.% solutions which were prepared by Cheng-Wei’s method are 680 and 2180 cP, respectively.

The morphologies of the electrospinning jet which obtained from 7 and 9 wt.% aqueous solutions which prepared in the two mentioned ways were observed with high speed camera. Regardless of prepared methods or solution concentrations, it seem that the electrospinning jet would break in a very short time. At the same concentration, the frequency of jet-break during the electrospinning of solutions which prepared by Cheng-Wei’s method is about 60 times higher than the solutions prepared by Ting-Yu’s method. In order to understand the jet behavior in whipping region, we measured the jet length, axial and lateral velocity of whipping wave at different time during the electrospinning of 7 wt.% aqueous solution which prepared by Ting-Yu’s method.

A small amount of the liquid jet was collected by the cover glasses. In the OM observation, there are some collected jet have oriented structure. The surface roughness of collected jet with oriented structure is smaller than that of jet without structure. Electrospinning jet is also collected by different glass slides containing the non-solvent, n-propanol. It was found the collected jet has some oriented structures. The are some linear and granular structures in the jet, and some nodules structures are discovered on the jet surface.

AFM results showed that the surface of as-spun PVA fibers were composed of regular and serrated structures. The width of these structures were found to be 0.98 nm. After shocking the as-spun PVA fiber in n-propanol solutions by ultrasonic liquid processor, there are some necked structures at the positions of jet break. These structures were probably related to the phase separation which occurred inside the electrospinning jet.

The ultrasonic shock of n-propanol solution contained as-spun PVA membranes was performed. It was found that low power is benefit to obtain good dispersion. After the ultrasonic shock of n-propanol soluiton, iPP powder was added to prepare the composite material. The dynamic crystallization behavior was characterized by OM and DSC. From the results, as-spun PVA fibers couldn’t induce the transcrystalline of iPP powder obtained from Formosa corporation.

[1] D. H. Reneker, A. L. Yarin, “Electrospinning jets and polymer nanofibers.”, Polymer, 49, 10, 2387 (2008).
[2] D. W. Clegg, A. A. Collyer “Mechanical Properties of Reinforced Thermoplastics.”, Springers, London, 2 (1986).
[3] F. G. Krautz, “Glass fiber enhanced high-temperature performance of thermoplastics.”, Society of Plastic Engineers, 27, 74 (1971).
[4] R. H. Burton, M. J. Folkes, “Interfacial morphology in short fibre reinforced thermoplastics.”, Plastic and Rubber Processing and Applications, 3, 2, 129 (1983).
[5] Y. Duan, H. Li, L. Li, D. Wang, S. Yan, X. Zhang, “Influence of crystallization temperature on the morphologies of isotactic polypropylene single-polymer composite.”, Polymer, 45, 23, 8059(2004).
[6] L. M. Wang, C. Wang, “Transcrystallization of PTFE fiber/PP composites (I) crystallization kinetics and morphology.”, Journal of Polymer Science Part B:Polymer Physics, 34, 1, 47 (1996).
[7] G. Binning, C. Gerber, C. F. Quate, “Atomic force microscope.”, Physical Review Letters, 56, 9, 930 (1986).
[8] 黃英碩, “掃描探針顯微術的原理及應用Scanning Probe Microscopy: Principles and Applications.”, 科儀新知, 26, 4, 7 (2005).
[9]李政霖, “含電紡同排聚乙烯纖維/聚丙烯複材之製備與熱性質”, 國立成功大學碩士論文 (2016).
[10] 李世元, 林世明, 林志成, “奈米量測技術－原子力顯微鏡在生物分子上之應用.”, 化學, 67, 1, 83 (2009).
[11] K. Kawanishi, M. Komtsu, T. Inouet, “Thermodynamic consideration of sol-gel transition in polymer solution.”, Polymer, 28, 6, 980(1987).
[12]J. D. Cho, W. S. Lyoo, S. N. Chvalun, J.Blackwell, “X-ray analysis and molecular modeling of poly(vinyl alcohol)s with different stereoregularities.”, Macromolecules, 32, 19, 6236 (1999).
[13] C. M. Hassan, N. A. Peppas, “Structure and morphology of freeze/thawed PVA hydrogels.”, Macromolecules, 33, 7, 2472 (2000).
[14] R. Endo, S. Amiya, M. Hikosaka, ”Condition for melt crystallization without thermal degradation and equilibrium melting temperature of atactic poly(vinyl alcohol).”, Journal of Polymer Science Part B: Physics, 42, 3-4, 793 (2003).
[15] C. Zhang, X. Yuan, L.Wu, Y. Han, J. Sheng, ” Study on morphology of electrospun poly(vinyl alcohol) mats.”, European Polymer Journal, 41, 3, 423 (2005).
[16] B. Ding, H. Y. Kim, S. C. Lee, D. R. Lee, K. J. Choi, ”Perparation and charaterization of nanoscaled poly(vinyl alcohol) fibers via electrospinning.”, Fiber and Polymer, 3, 2,73 (2002).
[17] A. Koski, K. Yim, S. Shivkumar, “Effect of molecular weight on fibrous PVA produced by electrospinning.”, Materials Letters, 58, 3-4,493 (2004).
[18] J. Zhao, Z. Sun, Z. Shao, L. Xu, “Effect of surface active angent on morphology and properties of electrospun PVA nanofibers.”, Fiber and Polymer, 17, 6, 896 (2016).
[19] B. Janković, J. Pelipenko, M. Škarabot, I. Muševič, J. Kristl, “The design trend in tissue-engineering scaffolds based on nanomechanical properties of individual electrospun nanofibers.”, International Journal of Pharmaceutics, 455, 1-2, 338 (2013).
[20] B. Lotz, A. Lovinger, J. C. Wittmann, “Structure and morphology of poly(propylenes): a molecular analysis.”, Polymer, 37, 22, 4979 (1996).
[21] S. Brűckner, S. V. Meille, V. Petraccone, B. Pirozzi, “Polymorphism in isotactic polypropylene.”, Progress in Polymer Science, 16, 2-3, 361 (1991).
[22] H. Bai, H. Deng, Q. Fu, F. Luo, K. Wang, T. Zhou “New insight on the annealing induced microstructural changes and their roles in the toughening of β-form polypropylene.”, Polymer, 52, 10, 2351 (2011).
[23] B. Lotz, K. Nakamura, N. Okui, S. Shimizu, A. Thierry, S. Umemoto, “Temperature dependence of crystal growth rate for  and  forms of isotactic polypropylene.”, Polymer Journal, 40, 9, 915 (2008).
[24] C. Wang, Y. L. Chu, Y. J. Wua, “Electrospun isotactic polystyrene nanofibers as a novel β-nucleating agent for isotactic polypropylene.”, Polymer, 53, 23, 5404 (2012).
[25] 陳怡君, “不同電紡纖維對聚丙烯穿經形成能力的影響”, 國立成功大學碩士論文 (2014).
[26] S. Zhao, H. Gong, X. Yu, Z. Xin, S. Sun, S. Zhou, Y. Shi, “A highly active and selective b-nucleating agent for isotactic polypropylene and crystallization behavior of -nucleated isotactic polypropylene under rapid cooling.”, Journal of Applied Polymer, 133, 32, 43767 (2016).
[27] J. Varga, K. Stoll, A. Menyhárd, Z. Horváth, “Crystallization of Isotactic Polypropylene in the Presence of a b-Nucleating Agent Based on a Trisamide of Trimesic Acid.”, Journal of Applied Polymer, 121, 3, 1469 (2011).
[28] D. W. Levi, P. C. Scherer, W. L. Hunter, K. Washimi, “Solvation of Polyvinyl Alcohol in Solvent-Nonsolvent Mixtures.”, Journal of polymer science, 28, 118, 481 (1958).
[29] X. Sun, T. Fujimoto, H. Uyama, “Fabrication of a poly(vinyl alcohol) monolith via thermally impacted non-solvent-induced phase separation.”, Polymer Journa, 45, 1101 (2013).
[30] V.G. Kulichikhin, Al.Ya. Malkin, Al.V. Semakov, I.Yu. Skvortsov, A. Arinstein, “Liquid filament instability due to stretch-induced phase separation in polymer solutions.”, The European Physical Journal E , 37, 10 (2014).
[31] M. Avrami, “Kinetics of phase change. I general theory.”, The Journal of Physical Chemistry B, 7, 12, 1103 (1939).
[32] M. Avrami, “Kinetics of phase change. II transformation‐time relations for random distribution of nuclei.”, The Journal of Physical Chemistry B, 8, 2, 212 (1940).
[33] I. Sons, J. Weliy, “Avrami analysis: three experimental limiting factors.”, Journal of Physical Science: Polymer Physics Edition, 18, 7, 1655 (1980).
[34] L. H. Sperling, “Introduction to physical polymer science.”, Wiley-Interscience, New York (1986).
[35] C. R. Liu, C. Wang, “Transcrystallization of polypropylene composites: nucleating ability of fibers.”, Polymer, 40, 2, 289 (1999).
[36] G. Edward, A. Phillips, P. W. Zhu, “Electrospun nanofiber-reinforced polypropylene composites: Nucleating ability of nanofibers.”, Composites Science and Technology , 126 , 1 (2016).