對排聚苯乙烯(syndiotactic polystyrene，sPS)，具有結晶快、高熔點以及機械性質佳等性質，是一種受到重視的工程塑膠。石墨烯為單層且具sp2二維結構的材料，導電性質優異且有良好的機械性質與熱傳導性。本研究將sPS與厚度約為1奈米(G1)與10奈米(G10)的石墨烯混摻製備成奈米複材，並研究其結晶行為、微結構、導電性。

SEM、TEM、AFM結果顯示，G1為充滿皺褶的片狀物，真實厚度小於2 nm，而G10為表面較為平滑的片狀物，真實厚度小於50 nm，此兩種石墨烯在溶劑中經超音波震盪處理後，橫向尺寸變小。由Raman光譜可知出純G1粉末比G10有更多的缺陷與sp3結構。

WAXD顯示，複材經melt quench熱處理會誘導sPS的晶型產生，試片切片後TEM影像可看出複材內條紋狀的sPS lamella，且G1在基材中分散較佳。Melt-quenched複材動態升降溫DSC結果顯示，石墨烯的摻入會使得複材冷結晶峰溫度變低、熔融結晶峰溫度升高，幫助sPS更容易結晶。等溫結晶動力學顯示石墨烯會降低sPS的Avrami 指數，並使整體結晶速率變快，且G10比G1提升結晶的效果較明顯。經由溶劑處理析出的sPS粉末其冷結晶會較原始sPS顆粒提早發生。

導電度量測結果顯示sPS/G1複材之導電percolation threshold為0.46 vol%，而sPS/G10複材之值為3.84 vol%，可知sPS/G1複材只需較少的石墨烯就能形成導電網路。

Syndiotactic polystyrene (sPS) possesses some unique properties, including high crystallization rate, high melting temperature and good mechanical strength. It is a noticeable engineering plastic. Graphene is a single layer material with sp2 2D structure, making graphene as a material with great mechanical ,electrical and thermal conductivity properties. In this research, we blend sPS and grapehene whith thickness of about 1 nm (G1) or 10 nm (G10) by a coagulation method to prepare nanocomposites. The microstructure, crystallization behavior and electrical properties of the as-prepared nanocomposites are studied..

SEM, TEM and AFM results show that G1 is a wrinkled flake and its real thickness is less than 2 nm. G10 is a sheet with a smoother surfacre and its real thickness is less than 50 nm. The lateral sizes of these two kinds of graphene are reduced after sonication in o-DCB solution. Raman spectra reveal that G1 powders have more defects and sp3 structure than G10 powders.

WAXD results show that melt-quenched nanocomposites produce the-form crystal of sPS. TEM results of the microtomed sample reveal that some striped lamella are developed in these melt-quenched nanocomposites and G1 fillers disperse more well in the sPS matrix.

Dynamic heating and cooling of DSC results show that the addition of graphene decreases the cold crystallization temperature and increases the melt crystallization temperature of melt-quenched samples. Addition of graphene declines the Avrami exponent and increases the overall crystallization rate of sPS. The cold crystallization peak of sPS coagulation powders is lower than that of the original sPS pellets.

From the electrical conductivity measurement, the percolation threshold of sPG/G1 composite is 0.46 vol%, and sPS/G10 is 3.84 vol%. Compared to the G10 fillers, lower G1 content is to form a conductivity network.

[1] J. Natta, “Une nouvelle classe de polymeres d’-olefines ayantune rkgularité de
structure exceptionnelle”, J. Polym. Sci. 16, 143 (1955).
[2] N. Ishihara, T. Seimiya, M. Kuramoto, M. Uoi, “Crystalline syndiotactic polystyrene”, Macromolecules 19, 2464 (1986).
[3] 吳中仁, “s-PS之特性與應用”, 化工資訊 12 (1996).
[4] 劉士榮, 高分子流變學, 滄海 (2005).
[5] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, A. A. Firsov, “ Electric field effect in atomically thin carbon films”, Science 306, 666 (2004).
[6] K. S. Kim, Y. Zhao, H. Jang, S. Y. Lee, J. M. Kim, K. S. Kim, J. H. Ahn, P. Kim, J. Y. Choi, B. H. Hong, “ Large-scale pattern growth of graphene films for stretchable transparent electrodes”, Nature 457, 706 (2009).
[7] Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, ”Graphene and graphene oxide: synthesis, properties, and applications”, Adv. Mater. 22, 3906 (2010).
[8] A.K. Geim,K.S. Novoselov, ” The rise of graphene”, Nat. Mater. 6,183 (2007).
[9] O.C. Compton, S.T. Nguyen, “ Graphene oxide, highly reduced graphene oxide, and graphene: Versatile building blocks for carbon-based materials”, Small 6, 711 (2010).
[10] O. Gries, Y. Xu, T. Asano, J. Petermann, “Morphology and structure of syndiotactic polystyrene”, Polymer 30, 590 (1989).
[11] C. De Rosa, G. Guerra, V. Petraccone, P. Corradini, “Crystal structure of the -form of syndiotactic polystyrene”, Polym. J. 23, 1435 (1991).
[12] Y. Chatani, Y. Fujii, Y. Shimane, T. Ijitsu, Polym. Prepr. Jpn. (Engl. Ed.) 37, E428 (1988).
[13] C. De Rosa, M. Rapacciuolo, G. Guerra, V. Petraccone, P. Corradini, “On the
crystal structure of the orthorhombic form of syndiotactic polystyrene”, Polymer
33, 1423 (1992).
[14] C. De Rosa, G. Guerra, P. Corradini, Rend. Fis. Acc. Lincei 2, 227 (1991).
[15] A. M. Evans, E. J. C. Kellar, J. Knowles, C . Galiotis, C. J.Carriere and E. H. Andrews, “The structure and morphology of syndiotactic polystyrene injection molded coupons”, Polym. Eng. Sci. 37, 153 (1997).
[16] S. Rastogi, J. G. P. Goossens, P. J. Lemstra, “An in situSAXS/WAXS/Raman spectroscopy study on the phase behavior ofsyndiotactic polystyrene(sPS)/solvent systems: compound formation andsolvent (dis)ordering”, Macromolecules 31, 2983 (1998).
[17] G. Guerra, V. M. Vitagliano, C. De Rosa, V. Petraccone, P. Corradini, “Polymorphism in melt crystallized syndiotactic polystyrene samples”, Macromolecules 23, 1539 (1990).
[18] H. D. Wu, I. D. Wu, F. C. Chang, “Characterization of crystallization in syndiotactic polystyrene thin film samples”, Macromolecule 33, 8915 (2000).
[19] H. D. Wu, S. C. Wu, I. D. Wu, F. C. Chang, “Novel determination of the crystallinity of syndiotactic polystyrene using FTIR spectrum”, Polymer 42, 4719 (2001).
[20] B. K. Hong, W. H. Jo, S. C. Lee, J. Kim, “Correlation between melting behaviour and polymorphism of syndiotactic polystyrene and its blend with poly(2,6-dimethyl-l,4-phenylene oxide)”, Polymer 39, 1793 (1998).
[21] J. Arnauts, H. Berghmans, “Equilibrium melting behavior of syndiotactic polystyrene”, Polym. Commun. 31, 343 (1990).
[22] E. M. Woo, F. S. Wu, “On the multiple melting behavior of polymorphic syndiotactic polystyrene and its behavior in a miscible state”, Macromol. Chem. Phys. 199, 2041 (1998).
[23] N. V. Gvozdic, D. J. Meier, “On the melting temperature of syndiotactic polystyrene”, Polym. Commun. 32, 183 (1991).
[24] N. V. Gvozdic, D. J. Meier, “On the melting temperature of syndiotactic polystyrene: 2. Enhancement of the melting temperature of semicrystalline polymers by a novel annealing procedure”, Polym. Commun. 32, 493 (1991).
[25] C. Wang, Y. C. Hsu, C. F. Lo, “Melting behavior and equilibrium melting temperatures of syndiotactic polystyrene in and crystalline forms”, Polymer 42, 8447 (2001).
[26] C. Lee, X. Wei, J. W. Kysar, J. Hone, “ Measurement of the elastic properties and intrinsic strength of monolayer graphene”, Science 321, 385 (2008).
[27] A. A. Balandin, S. Ghosh, W. Bao, I. Calizo, D. Teweldebrhan, “ Modification of graphene properties due to electron-beam irradiation”, Nano Lett. 8, 902 (2008).
[28] S. Ghosh, I. Calizo, D. Teweldebrhan, E. P. Pokatilov, D. L. Nika, A. A. alandin, W. Bao, F. Miao, C. N. Lau, “Thermal conductivity of graphene flakes: Comparison with bulk graphite”, Appl. Phys. Lett. 92, 151911 (2008).
[29] X. Wang, H. You, F. Liu, M. Li, L. Wan, S. Li, Q. Li, Y. Xu, R. Tian, Z. Yu, D. Xiang, J. Cheng, “ Large-scale synthesis of few-layered graphene using CVD”, Vapor Deposition 15, 53 (2009).
[30] N. Li, Z. Wang, K. Zhao, Z. Shi, Z. Gu, S. Xu, “ Large scale synthesis of N-doped multi-layered graphene sheets by simple arc-discharge method”, Carbon 48, 255 (2010).
[31] E. Rollings, G. Gweon, S. Y. Zhou, B. S. Mun, J.L. McChesney, B. S. Hussain, A. V. Fedorov, P. N. First, W. A. de Heer, A. Lanzar, ”Sythesis and chatcterization of automically thin graphite films on a silicon carbide subtrate”, J. Phys. Chem. Solids 67, 2172 (2006).
[32] W. Zhang, J. Cui, C. Tao, Y. Wu, Z. Li, L. Ma, Y. Wen, G. Li, ”A strategy for producing pure single-layer graphene sheets based on a confined self-assembly approach”, Angew. Chem. Int. Ed. 48, 5864 (2009).
[33] S. Stankovich, D. A. Dikin, R. D. Piner, K. A. Kohlhaas, A. Kleinhammes, Y. Jia, Y. Wu, S. T. Nguyen, R. S. Ruoff, ”Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide”, Carbon 45, 1558 (2007).
[34] H. C. Schniepp, J. L. Li, M. J. McAllister, H. Sai, M. Herrera-Alonso, D.H. Adamson, R. K. Prud’homme, R. Car, D. A. Saville, I. A. Aksay, ”Functionalized single graphene sheets derived from splitting graphite oxide”, J. Phys. Chem.B 110, 8535 (2006).
[35] N. Liu, F. Luo, H. Wu, Y. Liu, C. Zhang, ”One-step ionic-liquid-assisted electrochemical synthesis of ionic-liquid-functionalized graphene sheets directly from graphite”, J. Adv. Funct.Mater. 18, 1518 (2008).
[36] A. B. Bourlinos, V. Georgakilas, R. Zboril, T. A. Steriotis, A. Stubos, “Liquid-phase exfoliation of graphite towards solubilized graphenes”, Small 5, 1841 (2009).
[37] W. Scholz, H. P. Boehm, Z. Anorg. Allg. Chem., 369, 327–40(1969).
[38] L. M. Viculis, J. J. Mack, O. M. Mayer, H. T. Hahn, R. B. Kaner,”Intercalation and exfoliation routes to graphite nanoplatelets”, J. Mater. Chem. 15, 974 (2005).
[39] K. E. Carr, ”Intercalation and oxidation effects on graphite of a mixture of sulphuric and nitric acids”, Carbon 8, 155 (1970).
[40] H. Fukushima, Ph.D. Thesis, ”Graphite nanoreinforcements in polymer nanocomposites”, Michigan State University (2003).
[41] W. S. Hummers, R. E. Offernan, ” Preparation of graphitic oxide”, J. Am. Chem. Soc. 80, 1339 (1958).
[42] A. Buchstriner, A. Lerf, J. A. Pieper,” Water dynamics in graphite oxide investigated with neutron scattering”, J. Phys. Chem. B 110, 22328 (2006).
[43] M. J. McAllister, J. L. Li, D. H. Adamson, H. C. Schniepp, A. A. Abdala, J. Liu, M. Herrera-Alonso, D. L. Milius, R. Car, R. K. Prud’homme, I. A. Aksay, ” Single sheet functionalized graphene by oxidation and thermal expansion of graphite”, Chem. Mater. 19, 4396 (2007).
[44] S. Park, R. S. Ruoff, ”Chemical methods for the production of graphenes”, Nat. Nanotechnol 5, 217 (2009).
[45] D. R. Dreyer, S. Murali, Y. Zhu, R. S. Ruoff, C. W. Bielawski, “ Reduction of graphite oxide using alcohols”, J. M. Chem. 21, 3443 (2011).
[46] J. Zhang, H. Yang, G. Shen, P. Cheng, J. Zhang, S. Guo,” Reduction of graphene oxide via L-ascorbic acidw”, Chem. Commun. 46, 1112 (2010).
[47] S. Stankovich, D. A. Dikin, G. H. B. Dommett, K. M. Kohlhaas, E.J. Zimney, E. A. Stach, R. D. Piner, S. T. Nguyen, R. S. Ruoff, ” Graphene-based composite materials”, Nature 442, 282 (2006).
[48] S. Park, J. An, R. D. Piner, I. Jung, D. Yang, A. Velamakanni, S. T. Nguyen, R. S. Ruoff, “ Aqueous suspension and characterization of chemically modified graphene sheets”, Chem. Mater. 20, 6592 (2008).
[49] Y. Gao, J. Feng, P. Wu, ” Preparation of organically dispersible graphene nanosheet powders through a lyophilization method and their poly(lacticacid) composites”, Carbon 48, 3834 (2010).
[50] F. Gubbels, R. Jérôme, Ph. Teyssié, E. Vanlathem, R. Deltour, A.Calderone, V. Parenté, J. L. Brédas, “Selective localization of carbon black in immiscible polymer blends: A useful tool to design electrical conductive composites”, Macromolecules 27, 1972 (1994).
[51] F. Gubbels, S. Blacher, E. Vanlathem, R. Jérôme, J R. Deltour, F.Brouers, Ph. Teyssié, “Design of electrical conductive composites: Key role of the morphology on the electrical properties of carbon black filled polymer blends”, Macromolecules 28, 1559 (1995).
[52] H. Kim, Y. Miura, C. W. Macosko, ” Graphene/polyurethane nanocomposites for improved gas barrier and electrical conductivity”, Chem.Mater. 22,3441 (2010).
[53] S. Ansari, E. P. Giannelis, ”Functionalized graphene sheet—poly(vinylidene fluoride) conductive nanocomposites”, Polym. Phy. 47, 888 (2009).
[54] H. B. Zhang, W.G. Zheng, Q. Yan, Y. Yang, J. W. Wang, Z. H. Lu, ” Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding”, Polymer 51, 1191 (2005).
[55] I. H. Kim, Y. G. Jeong, “ Polylactide/exfoliated graphite nanocomposites with enhanced thermal stability, mechanical modulus, electrical conductivity”, J. Polym. Sci. Part B Polym. Phys. 48, 850 (2010).
[56] K. Kalaitzidou, H. Fukushima, L. T. Drzal, ” Mechanical properties and morphological characterization of exfoliated graphite–polypropylene nanocomposites”, Compos. Part A Appl. Sci. Manuf. 38 , 1675 (2007).
[57] H. C. Schniepp, J. L. Li, M. J. McAllister, H. Sai, M. Herrera-Alonso, D. H. Adamson, ”Oxygen-driven unzipping of graphitic materials”, J. Phys. Chem. B 110, 8535 (2006).
[58] H. Shioyama, ”Polymerization of isoprene and styrene in the interlayer spacing of graphite”, Carbon 35 , 1664 (1997).
[59] Y. X. Pan, Z. Z. Yu, Y. C. Ou, G. H. Hu, ” A new process of fabricating electrically conducting nylon 6/graphite nanocomposites via intercalation polymerization”, J. Polym. Sci. Part B Polym. Phys. 38, 1626 (2000).
[60] F. C. Fim, J. M. Guterres, N. R. S. Basso, G. B. Galland, ” Polyethylene/graphite nanocomposites obtained by in situ polymerization”, J. Polym. Sci. Part A Polym. Chem. 48, 692 (2010).
[61] J.Y. Jang, M. S. Kim, H. M. Jeong, C. M. Shin, “Graphite oxide/poly(methyl methacrylate) nanocomposites prepared by a novel method utilizing macroazoinitiator”, Compos. Sci. Technol. 69, 186 (2009).
[62] H. Kim, Y. Miura, C. W. Macosko, ” Graphene/polyurethane nanocomposites for improved gas barrier and electrical conductivity”, Chem. Mater. 22, 3441 (2010).
[63] M. Alexandre, P. Dubois, “Polymer-layered silicate nanocomposites: preparation, propertiesand uses of a new class of materials”, Mater. Sci. Eng. R. Rep. 28, 1 (2000).
[64] L. S. Schadler, L. C. Brinson, W. G. Sawyer, J. Miner. Met. Mater. Soc., 59, 53 (2007).
[65] J. J. Liang, Y. Huang, L. Zhang, Y. Wang, Y. F. Ma, T. Y. Guo, “Molecular-level dispersion of graphene into poly(vinyl alcohol) and effective reinforcement of their nanocomposites”, Adv. Funct. Mater. 19, 2297 (2009).
[66] D. Y. Cai, M. Song, “A simple route to enhance the interfacebetween graphite oxide nanoplatelets and a semi-crystalline polymer for stresstransfer”, Nanotechnology 20, 315708 (2009).
[67] S. Ansari, A. Kelarakis, L. Estevez, E. P. Giannelis, “Oriented arrays of graphene in a polymer matrix by in situ reduction of graphite oxide nanosheets”, Small 6,205 (2010).
[68] W. Zheng, X. Lu, S. C. Wong, “Electrical and mechanical properties of expanded
graphite-reinforced high-density polyethylene”, J. Appl. Polym. Sci. 91, 2781 (2004).
[69] X. Yang, L. Li, S. Shang, X. M. Tao, “Synthesis and characterization of layer-aligned poly(vinyl alcohol)/graphene nanocomposites”, Polymer 51, 3431 (2010).
[70] S. Ansari, E. P. Giannelis, “Functionalized graphene sheet—poly(vinylidene fluoride) conductive nanocomposites”, J. Polym. Sci., Polym. Phys. Ed. 47, 888 (2009).
[71] J. Z. Xu, T. Chen, C. L. Yang, Z. M. Li, Y. M. Mao, B. Q. Zeng, “Dopamine-induced reduction and functionalization of graphene oxide nanosheets”, macromolecules 43,5000 (2010).
[72] S. Cheng, X. Chen, Y. G. Hsuan, C. Y. Li, “Reduced graphene oxide-induced polyethylene crystallization in Solution and nanocomposites”, Macromolecules 45, 993(2012).
[73] D. U. Fangming, R. C. Scogna, W. Zhou, S. Brand, J. E. Fischer, K. I. Winey, “Nanotube networks in polymer nanocomposites: rheology and electrical conductivity”, Macromolecules 37, 9048 (2004).
[74] P. Pötschke, M. Abdel-Goad, I. Alig, S. Dudkin, D. Lellinger, “Rheological and dielectrical characterization of melt mixed polycarbonate-multiwalled carbon nanotube composites”, Polymer 45, 8863 (2004).
[75] H. Kim, C. W. Macosko, ” Processing-property relationships of polycarbonate/graphene composites”, Polymer 50, 3797 (2009).
[76] J. D. Hoffman, J. J. Weeks, “Melting process and the equilibrium melting temperature of polychlorotrifluoroethylene”, J. Res. Natl. Bur. Stand. (U.S.), A66,
16 (1962).
[77] M. Avrami, “Kinetics of phase change. I General theory”, J. Chem. Phys. 7, 1103 (1939).
[78] M. Avrami, “Kinetics of phase change. II Transformation-time relationsfor random distribution of nuclei”, J. Chem. Phys. 8, 212 (1939).
[79] J. Weliy, I. Sons, “Avrami analysis: Three experimental limitingfactors”,
J. Polym. Sci. Polym. Phys. Ed. 18, 1655 (1980).
[80] L. H. Sperling, “Introduction to physical polymer science”, Wiley-Interscience, New York (1986).
[81] F. J. Balta-Calleja, C. G. Vonk, “X-ray scattering of synthetic polymers”, Elserier, New York (1989).
[82] H. Kim, A. A. Abdala, C. W. Macosko, ”Graphene/polymer nanocomposites”, Macrmolecules 43, 6515 (2010).
[83] H.C. Schniepp, J. L. Li, M. J. McAllister, H. Sai, M. Herrera-Alonso, D. H. Adamson, R. K. Prud'homme, R. Car, D. A. Saville, I. A. Aksay, “Functionalized single graphene sheets derived from splitting graphite oxide”, J. Phys. Chem. B. 110, 8535 (2006).
[84] G. Guerra, V. M. Vitagliano, C. De Rosa, V. Petraccone, P. Corradini, “Polymorphism in melt crystallized syndiotactic polystyrene samples”, Macromolecules 23, 1539 (1990).
[85] G. Guerra, V. M. Vitagliano, C. De Rosa, V. Petraccone, P. Corradini, “Polymorphism in melt crystallized syndiotactic polystyrene samples”, Macromolecules 23, 1539 (1990).
[86] B. Z. Jang, A. A. Zhamu, ”Processing of nanographene platelets (NGPs) and NGP
nanocomposites: a review”, J. Mater. Sci. 43, 5092 (2008).
[87] A. C. Ferrari, J. C. Meyer, V. Scardaci, C. Casiraghi, M. Lazzeri, F. Mauri, S. Piscanec, D. Jiang, K. S. Novoselov, S. Roth, A. K. Geim, “Raman spectrum of graphene and graphene layers”, Phys. Rev. Lett. 97, 187401 (2006).
[88] G. Srinivas, Y. Zhu, R. Piner, N. Skipper, M. Ellerby, R. Ruoff, “Synthesis of graphene-like nanosheets and their hydrogen adsorption capacity”, Carbon 48, 630 (2010).
[89] D. W. Schaefer, R. S. Justice, ” How nano are nanocomposites?”, Macromolecules 40, 8501 (2007).
[90] I. Balberg, “Tunneling and nonuniversal conductivity in comoposites materials”, Phys Rev Lett 59, 1305 (1987).
[91] X. Wu, S. Qi, J. He, G. Duan, ”High conductivity and low percolation threshold in polyaniline/graphite nanosheets composites” J. Mater. Sci. 45, 483 (2010).
[92] H. Pang, T. Chen, G. Zhang, B. Zeng, Z. M. Li, ”An electrically conducting polymer/graphene composite with a very low percolation threshold”, Mater. Lett. 64, 2226 (2010).
[93] M. Yoonessi, J. R. Gaier, “Highly conductive multifunctional graphene polycarbonate nanocomposites”, ACS Nano 4, 7211 (2010).
[94] J. Lianga, Y. Wanga, Y. Huanga, Y. Maa, Z. Liua, J. Caib, C. Zhangb, H. Gaob, Y. Chen, “Electromagnetic interference shielding of graphene/epoxy composites”, Carbon 47, 922 (2009).
[95] Z. H. Ni, W. Chen, X. F. Fan, J. L. Kuo, T. Yu, A. T. S. Wee, Z. X. Shen, “Raman spectroscopy of epitaxial graphene on a SiC substrate”, Phys. Rev. B 77, 115416 (2008).
[96] K. Kalaitzidou, H. Fukushima, L. T. Drzal, “Liquid phase production of graphene by exfoliation of graphite in surfactant/water solutions”, Carbon 45, 1446 (2007).
[97] M. Lotya, Y. Hernandez, P. J. King, R. J. Smith, V. Nicolosi, L. S. Karlsson, “Liquid phase production of graphene by exfoliation of graphite in surfactant/water Solutions”, J. Am. Chem. Soc. 131, 3611 (2009).
[98] X. Li, G. Zhang, X. Bai, X. Sun, X. Wang, E. Wang, H. Dai, ”Highly conducting graphene sheets and Langmuir–Blodgett films”, Nat. Nanotechnol. 3, 538 (2008).
[99] C. L. Huang, C. Wang, “Polymorphism and transcrystallization of syndiotactic polystyrene composites filled with carbon nanotubes”, Euro. Polym. J. 47, 2087 (2011).