許多的高分子複合材料舉凡聚甲基丙烯酸甲酯(PMMA)、聚苯乙烯(PS)、聚碳酸酯(PC)都利用添加奈米碳管來增強塑性高分子基地相的性質，這方面的研究在長時間下所累積的成果已不勝枚舉。而隨著奈米碳管添加量的上升，複合材料的機械強度會有很顯著的提升。本論文分別針對聚甲基丙烯酸甲酯/奈米碳管複合材料硬度的演變及潛變量測試做研究，接著透過理論分析探討導致其性質演變的可能機制。
由實驗結果發現，硬度會隨著退火溫度及奈米碳管摻雜量的增加而增加、隨著紫外光照射量的增加而減少。硬度的改變可以歸因於缺陷在材料微結構中的變化，我們利用一階動力學模型來解釋缺陷的動態變化過程。由此所得的速率常數符合Arrhenius equation且反應活化能隨著紫外光照射量的增加而減少、隨著奈米碳管摻雜量增加而增加。
由潛變測試我們可以得知，應變量會隨著退火溫度及紫外光照射量的增加而增加、隨著奈米碳管摻雜量的增加而減少。我們利用standard linear solid model來試著了解其中的機制，模擬結果所得的黏度係數和Arrhenius equation是吻合的，其所對應到的反應活化能會隨著紫外光的增加而減少、隨著奈米碳管摻雜量增加而增加。

The use of multi-walled carbon nanotubes (MWCNTs) as reinforcing materials for thermoplastic polymer matrices, such as poly(methyl methacrylate) (PMMA), polystyrene (PS) and polycarbonate (PC), has been studied extensively. A considerable improvement on mechanical properties of the composite can be observed when the mass fraction of MWCNTs increases. In the thesis, we investigated the evolution of hardness, the trace of creep and stress relaxation behavior in PMMA/MWCNTs composites, respectively.
Hardness increases with increasing annealing temperature and contents of MWCNTs, but decreases with increasing UV doses. The hardness change is attributed to the variation of defects in microstructure. The kinetics of defects follow a first-order kinetic model. Furthermore, the rate constant satisfies the Arrhenius equation, and the corresponding activation energy increases with increasing contents of MWCNTs and decreasing UV doses.
It was found for PMMA/MWCNTs composites that the creep strain increases with increasing annealing temperature and UV doses and decreases with increasing contents of MWCNTs. To understand the mechanism, the standard linear solid model is employed. The viscosity coefficient obeys the Arrhenius equation, and the corresponding activation energy increases with increasing contents of MWCNTs and decreasing UV doses.

References

[1] S. Iijima, Helical microtubules of graphitic carbon, Nature 354 (1991) pp.56-58.
[2] V. Mittal, Polymer Nanotube Nanocomposites: Synthesis, Properties, and Applications, Wiley (2010), New York City, United States.
[3] R.S. Ruoff, D. Qian, W.K. Liu, Mechanical properties of carbon nanotubes: theoretical predictions and experimental measurements, Comptes Rendus Physique 4 (2003) pp.993-1008.
[4] C. Kittel, D.F. Holcomb, Introduction to solid state physics, American Journal of Physics 35 (1967) pp.547-548.
[5] P.R. Bandaru, Electrical properties and applications of carbon nanotube structures, Journal of Nanoscience and Nanotechnology 7 (2007) pp.1239-1267.
[6] Y. Luo, J. Zhang, N. Xi, H. Chen, W.C. Lai, K.M. Fung, T.J. Tarn, Engineering the band gap of carbon nanotubes, 8th IEEE conference on Nanotechnology (2008) pp. 183-186.
[7] J.W. Che, T. Cagin, Thermal conductivity of carbon nanotubes, Nanotechnology 11 (2000) pp.65-69.
[8] A.E. Aliev, M.H. Lima, E.M. Silverman, R.H. Baughman, Thermal conductivity of multi-walled carbon nanotube sheets: radiation losses and quenching of phonon modes, Nanotechnology 21 (2009) 035709.
[9] Z. Spitalsky, D. Tasis, K. Papagelis, C. Galiotis, Carbon nanotube–polymer composites: chemistry, processing, mechanical and electrical properties, Progress in polymer science 35 (2010) pp.357-401.
[10] B.W. Steinert, D.R. Dean, Magnetic field alignment and electrical properties of solution cast PET–carbon nanotube composite films, Polymer 50 (2009) pp.898-904.
[11] N.A. Isitman, C. Kaynak, Nanoclay and carbon nanotubes as potential synergists of an organophosphorus flame-retardant in poly (methyl methacrylate), Polymer Degradation and Stability 95 (2010) pp.1523-1532.
[12] T. Kuila, S. Bose, C.E. Hong, M.E. Uddin, P. Khanra, N.H. Kim, J.H. Lee, Preparation of functionalized graphene/linear low density polyethylene composites by a solution mixing method, Carbon 49 (2011) pp.1033-1037.
[13] F. Xin, L. Li, Decoration of carbon nanotubes with silver nanoparticles for advanced CNT/polymer nanocomposites, Composites Part A: Applied Science and Manufacturing 42 (2011) pp.961-967.
[14] M. Ma, Z. Zhu, B. Wu, S. Chen, Y. Shi, X. Wang, Preparation of highly conductive composites with segregated structure based on polyamide-6 and reduced graphene oxide, Materials Letters 190 (2017) pp.71-74.
[15] P. Kalakonda, S. Banne, Thermomechanical properties of PMMA and modified SWCNT composites, Nanotechnology, science and applications 10 (2017) pp.45-52.
[16] F.M. DU, J.E. Fischer, K.I. Winey, Coagulation method for preparing single‐walled carbon nanotube/poly (methyl methacrylate) composites and their modulus, electrical conductivity, and thermal stability, Journal of Polymer Science Part B: Polymer Physics 41 (2003) pp.3333-3338.
[17] P. Pötschke, A.R. Bhattacharyya, A. Janke, S. Pegel, A. Leonhardt, C. Täschner, M. Ritschel, S. Roth, B. Hornbostel, Melt mixing as method to disperse carbon nanotubes into thermoplastic polymers, Fullerenes, nanotubes, and carbon nanostructures 13 (2005) pp.211-224.
[18] B. Krause, P. Pötschke, L. Häußler, Influence of small scale melt mixing conditions on electrical resistivity of carbon nanotube-polyamide composites, Composites Science and Technology 69 (2009) pp.1505-1515.
[19] A. Göldel, A. Marmur, G.R. Kasaliwal, P. Pötschke, G. Heinrich, Shape-dependent localization of carbon nanotubes and carbon black in an immiscible polymer blend during melt mixing, Macromolecules 44 (2011) pp.6094-6102.
[20] B. Krause, T. Villmow, R. Boldt, M. Mende, G. Petzold, P. Pötschke, Influence of dry grinding in a ball mill on the length of multiwalled carbon nanotubes and their dispersion and percolation behaviour in melt mixed polycarbonate composites, Composites Science and Technology 71 (2011) pp.1145-1153.
[21] R. Haggenmueller, H.H. Gommans, A.G. Rinzler, J.E. Fischer, K.I. Winey, Aligned single-wall carbon nanotubes in composites by melt processing methods, Chemical Physics Letters 330 (2000) pp.219-225.
[22] W.A. Curtin, B.W. Sheldon, CNT-reinforced ceramics and metals, Materials Today 7 (2004) pp.44-49.
[23] Takashi Kashiwagi, B. Morgan, J.M. Antonucci, R.H.H. Jr., E.A. Grulke, J.N. Hilding, J.F. Douglas, Thermal Degradation and Flammability Properties of Nanocomposites, Advances in Polymer Technology 36 (2017) pp.137-144.
[24] M. Lahelin, M. Annala, A. Nykänen, J. Ruokolainen, J. Seppälä, In situ polymerized nanocomposites: Polystyrene/CNT and Poly (methyl methacrylate)/CNT composites, Composites Science and Technology 71 (2011) pp.900-907.
[25] M.A. Pantoja-Castro, J.F. Pérez-Robles, H. González-Rodríguez, Y. Vorobiev-Vasilievitch, H.V. Martínez-Tejada, C. Velasco-Santos, Synthesis and investigation of PMMA films with homogeneously dispersed multiwalled carbon nanotubes, Materials Chemistry and Physics 140 (2013) pp.458-464.
[26] P.H.d.S.L. Coelho, M.S. Marchesin, A.R. Morales, J.R. Bartoli, Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites, Materials Research 17 (2014) pp.127-132.
[27] A.K. Mikitaev, G.V. Kozlov, Structural model for the reinforcement of polymethyl methacrylate/carbon nanotube nanocomposites at an ultralow nanofiller content, Technical Physics 61 (2016) pp.1541-1545.
[28] M.U. Khan, V.G. Gomes, Influence of chain transfer agent on structure/property relation of polymer nanocomposites with functionalized carbon nanotubes, Composites Part A: Applied Science and Manufacturing 11 (2017) pp.353-359.
[29] T. Kashiwagi, J. Fagan, J.F. Douglas, K. Yamamoto, A.N. Heckert, S.D. Leigh, J. Obrzut, F. Du, S. Lin-Gibson, M. Mu, Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites, Polymer 48 (2007) pp.4855-4866.
[30] U. Staudinger, P. Thoma, F. Lüttich, A. Janke, O. Kobsch, O.D. Gordan, P. Potschke, B. Voit, D.R.T. Zahn, Properties of thin layers of electrically conductive polymer/MWCNT composites prepared by spray coating, Composites Science and Technology 138 (2017) 134-143.
[31] M.S. Alkuh, M.H.N. Famili, M.M.M. Shirvan, M.H. Moeini, The relationship between electromagnetic absorption properties and cell structure of poly (methyl methacrylate)/multi-walled carbon nanotube composite foams, Materials & Design 100 (2016) pp.73-83.
[32] S. Fakher, R. Nejm, A. Ayesh, A. AL-Ghaferi, D. Zeze, M. Mabrook, Single-walled carbon-nanotubes-based organic memory structures, Molecules 21 (2016) 1166.
[33] U. Ali, K.J.B. Abd Karim, N.A. Buang, S. Hashim, Influence of poly (methyl methacrylate) grafted multiwalled carbon nanotubes on the mechanical and thermal properties of natural rubber nanocomposites, Journal of Composite Materials 51 (2017) pp.1-8.
[34] E. Yousif, R. Haddad, Photodegradation and photostabilization of polymers, especially polystyrene, SpringerPlus 2 (2013) pp.398-430.
[35] S. Eve, J. Mohr, Study of the surface modification of the PMMA by UV-radiation, Procedia Engineering 1 (2009) pp.237-240.
[36] P. Delobelle, L. Guillot, C. Dubois, L. Monney, Photo-oxidation effects on mechanical properties of epoxy matrixes: Young's modulus and hardness analyses by nano-indentation, Polymer Degradation and Stability 77 (2002) pp.465-475.
[37] I.A. Hussein, Rheological investigation of the influence of molecular structure on natural and accelerated UV degradation of linear low density polyethylene, Polymer Degradation and Stability 92 (2007) pp.2026-2032.
[38] B. Singh, N. Sharma, Mechanistic implications of plastic degradation, Polymer Degradation and Stability 93 (2008) pp.561-584.
[39] M.Y. Li, Y.F. Chuang, F. Yang, S. Lee, Evolution of color centers in UV-irradiated syndiotactic polystyrene at elevated temperatures, Materials Research Express 4 (2017) 025301.
[40] S.Y. Lee, H.S. Yang, H.J. Kim, C.S. Jeong, B.S. Lim, J.N. Lee, Creep behavior and manufacturing parameters of wood flour filled polypropylene composites, Composite Structures 65 (2004) pp.459-469.
[41] M.J. Yang, Y.M. Zhao, N. Zhang, Creep behavior of epoxy-bonded anchor system, International Journal of Rock Mechanics and Mining Sciences 67 (2014) pp.96-103.
[42] M.J. Cadena, R. Misiego, K.C. Smith, A. Avila, B. Pipes, R. Reifenberger, A. Raman, Sub-surface imaging of carbon nanotube–polymer composites using dynamic AFM methods, Nanotechnology 24 (2013) 135706.
[43] E.T. Thostenson, T.-W. Chou, Aligned multi-walled carbon nanotube-reinforced composites: processing and mechanical characterization, Journal of physics D: Applied physics 35 (2002) pp.77-80.
[44] G.C. Sih, Handbook of Stress: intensity Factors, Lehigh University, Institute of Fracture and Solid Mechanics (1973) pp.1.2.4-1.
[45] J.C. Hsu, W.X. Cao, F.Q. Yang, T.J. Yang, S. Lee, Absorption behavior of poly (methyl methacrylate)–multiwalled carbon nanotube composites: effects of UV irradiation, Physical Chemistry Chemical Physics 19 (2017) pp.7359-7369.
[46] J. Kowalonek, H. Kaczmarek, M. Kurzawa, Effect of UV-irradiation on fluorescence of poly (methyl methacrylate) films with photosensitive organic compounds, Journal of Photochemistry and Photobiology A: Chemistry 319 (2016) pp.18-24.
[47] Z. Jia, Z. Wang, C. Xu, J. Liang, B. Wei, D. Wu, S. Zhu, Study on poly (methyl methacrylate)/carbon nanotube composites, Materials Science and Engineering: A 271 (1999) pp.395-400.
[48] C. Wochnowski, M.A.S. Eldin, S. Metev, UV-laser-assisted degradation of poly(methyl methacrylate), Polymer Degradation and Stability 89 (2005) pp.252-264.
[49] K.P. Lu, S. Lee, C.P. Chen, Hardness of irradiated poly (methyl methacrylate) at elevated temperatures, Journal of Applied Physics 90 (2001) pp.1745-1749.
[50] Z. Zhang, J.-L. Yang, K. Friedrich, Creep resistant polymeric nanocomposites, Polymer 45 (2004) pp.3481-3485.
[51] M. Ganß, B.K. Satapathy, M. Thunga, R. Weidisch, P. Pötschke, A. Janke, Temperature dependence of creep behavior of PP–MWNT nanocomposites, Macromolecular rapid communications 28 (2007) pp.1624-1633.
[52] D.R. Bortz, M. Weisenberger, B. Marrs, R. Andrews, Fatigue performance of multiwall carbon nanotube composite PMMA and ABS, ASME 2008 International Mechanical Engineering Congress and Exposition: American Society of Mechanical Engineers (2008) pp. 235-242.
[53] M.R. VANLANDINGHAM, R.F. EDULJEE, J.W. GILLESPIE, Relationships between stoichiometry, microstructure, and properties for amine‐cured epoxies, Journal of Applied Polymer Science 71 (1999) 699-712.
[54] S.Y. Madani, A. Mandel, A.M. Seifalian, A concise review of carbon nanotube's toxicology, Nano reviews 4 (2013) 21521.