奈米碳管具有不錯的導電、導熱及高機械強度，在複合材料中是常見的強化材料，聚甲基丙烯酸甲酯(PMMA)有很好的硬度、拉伸強度及良好的透光度，是生活中常見的熱塑性材料，我們結合兩者合成出奈米碳管與聚甲基丙烯酸甲酯複合材料。裂縫癒合可以幫助延長材料的使用壽命，裂縫癒合的方法有很多種，我們採用溶劑癒合，我們查詢以前的文章得知甲醇可以幫助PMMA進行裂縫癒合，我們針對奈米碳管的添加影響甲醇癒合效率及加入甲醇後的表面進行實驗觀察，並做紫外光的照射觀察奈米碳管在複合材料中的影響。
由實驗結果可以知道，加入奈米碳管可以提升拉伸強度及玻璃轉換溫度上升，甲醇的加入可以降低PMMA的玻璃轉換溫度使裂縫癒合發生，奈米碳管會降低甲醇擴散進入的速度，且在PMMA癒合的效率上添加奈米碳管的複合材料也沒有較好的結果。藉由浸泡甲醇後放進二甲基甲醯胺中，表面會產生細微裂縫，對應甲醇質傳的結果，甲醇擴散進入PMMA後會些微膨脹，二甲基甲醯胺會吸出甲醇產生拉伸內應力，因此在把甲醇吸出後表面會產生細微裂紋，我們可以進一步證實PMMA在浸泡甲醇後會膨脹在表面產生壓縮應力並幫助PMMA裂縫的癒合。
在照射紫外光後，PMMA會發生光降解反應，主鍊會斷鍊並降低分子量，在UV 248 nm 下部分PMMA會發生交連現象，使玻璃轉換溫度增加並提升楊氏模數，但隨著紫外光劑量增加，斷鍊的情形會更嚴重，加入奈米碳管後，因為碳管不會受紫外光影響，進而形成一層保護層保護內部的PMMA使紫外光影響降低，機械強度在紫外光劑量增加後不會降低太多，而在裂縫癒合方面，甲醇因PMMA在受到紫外光照射下變成較小的分子，所以相對容易進入PMMA高分子鍊間的孔洞且質傳速率較快，而加入碳管後癒合的強度與純PMMA強度差不多，由上述實驗可知奈米碳管雖然可以幫助增加拉伸強度的提升及降低紫外光的影響，但在裂縫癒合方面反而沒有幫助。

Muti-wall carbon nanotube (MWCNT) has good electric conductivity, thermal conductivity and high mechanical strength. Poly (methyl methacrylate) (PMMA) have high hardness, tensile stress and transparent. We mixed these two materials to get higher strength than pure PMMA. The crack-healing for PMMA can be done by methanol transport from previous researches. We wonder whether the MWCNT will help healing or not. PMMA/MWCNT composites will be strengthened by adding MWCNT. The diffusion coefficient for Case I transport and velocity for Case II transport of composite will decrease with the increase of the concentration of MWCNTs. Also, the crack closure rate of composite will decrease because MWCNT played an obstructer to heal. The healed stress of composite is not good for adding MWCNT. Methanol will swell the PMMA and induce compressive stress near the surface, so that this will help crack-healing. We also observed the surface morphology of composite that immersed in methanol first, then put it into 2EA. We put it into 2EA after immersed in methanol to extract the methanol. The surface layer will produce small cracks due to the tensile stress induced by methanol desorption. UV irradiation will degrade the PMMA, so we study the property changes of irradiated PMMA when we added MWCNT. With UV dose, PMMA will go photo degradation reaction and lower down the molecular weight. UV 248 nm will cause some part doing cross-linking reaction to rise the Young’s modulus and glass-transition temperature. Because MWCNT cannot react with UV irradiation, it will protect inner PMMA and lower down the effect of UV irradiation.

1. U. Ali, K.J.B.A. Karim, N.A. Buang, "A review of the properties and applications of poly (methyl methacrylate)(PMMA)". Polymer Reviews 55, 678-705 (2015).
2. X. Sun, H. Sun, H. Li, H. Peng, "Developing polymer composite materials: carbon nanotubes or graphene?". Advanced Materials 25, 5153-5176 (2013).
3. V.D. Punetha, S. Rana, H.J. Yoo, A. Chaurasia, J.T. McLeskey Jr, M.S. Ramasamy, N.G. Sahoo, J.W. Cho, "Functionalization of carbon nanomaterials for advanced polymer nanocomposites: a comparison study between CNT and graphene". Progress in Polymer Science 67, 1-47 (2017).
4. M.T. Byrne, Y.K. Gun'ko, "Recent advances in research on carbon nanotube–polymer composites". Advanced Materials 22, 1672-1688 (2010).
5. G. Chen, W. Weng, D. Wu, C. Wu, "PMMA/graphite nanosheets composite and its conducting properties". European Polymer Journal 39, 2329-2335 (2003).
6. G. Pandey, E.T. Thostenson, "Carbon nanotube-based multifunctional polymer nanocomposites". Polymer Reviews 52, 355-416 (2012).
7. S.J. Park, M.S. Cho, S.T. Lim, H.J. Choi, M.S. Jhon, "Electrorheology of multiwalled carbon nanotube/poly (methyl methacrylate) nanocomposites". Macromolecular rapid Communications 26, 1563-1566 (2005).
8. C. Laurent, E. Flahaut, A. Peigney, "The weight and density of carbon nanotubes versus the number of walls and diameter". Carbon 48, 2994-2996 (2010).
9. O. Breuer, U. Sundararaj, "Big returns from small fibers: a review of polymer/carbon nanotube composites". Polymer Composites 25, 630-645 (2004).
10. G. Mittal, V. Dhand, K.Y. Rhee, S.-J. Park, W.R. Lee, "A review on carbon nanotubes and graphene as fillers in reinforced polymer nanocomposites". Journal of Industrial and Engineering Chemistry 21, 11-25 (2015).
11. N. Roy, R. Sengupta, A.K. Bhowmick, "Modifications of carbon for polymer composites and nanocomposites". Progress in Polymer Science 37, 781-819 (2012).
12. F.L. Jin, S.J. Park, "A review of the preparation and properties of carbon nanotubes-reinforced polymer compositess". Carbon letters 12, 57-69 (2011).
13. Z. Spitalsky, D. Tasis, K. Papagelis, C. Galiotis, "Carbon nanotube–polymer composites: chemistry, processing, mechanical and electrical properties". Progress in Polymer Science 35, 357-401 (2010).
14. R. Mathur, S. Pande, B. Singh, "Properties of PMMA/carbon nanotubes nanocomposites". Polymer Nanotube Nanocomposites: Synthesis Properties, and Applications 11, 177 (2010).
15. J. Zeng, B. Saltysiak, W. Johnson, D.A. Schiraldi, S. Kumar, "Processing and properties of poly (methyl methacrylate)/carbon nanofiber composites". Composites Part B: Engineering 35, 245-249 (2004).
16. S.J. Park, M.S. Cho, S.T. Lim, H.J. Choi, M.S. Jhon, "Synthesis and dispersion characteristics of multi‐walled carbon nanotube composites with poly (methyl methacrylate) prepared by in‐situ bulk polymerization". Macromolecular Rapid Communications 24, 1070-1073 (2003).
17. 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, 900-907 (2011).
18. S.T. Kim, J.Y. Lim, B.J. Park, H.J. Choi, "Dispersion‐Polymerized Carbon Nanotube/Poly (methyl methacrylate) Composite Particles and their Electrorheological Characteristics". Macromolecular Chemistry and Physics 208, 514-519 (2007).
19. M.H. Al-Saleh, U. Sundararaj, "Review of the mechanical properties of carbon nanofiber/polymer composites". Composites Part A: Applied Science and Manufacturing 42, 2126-2142 (2011).
20. I.D. Rosca, F. Watari, M. Uo, T. Akasaka, "Oxidation of multiwalled carbon nanotubes by nitric acid". Carbon 43, 3124-3131 (2005).
21. K. Behler, S. Osswald, H. Ye, S. Dimovski, Y. Gogotsi, "Effect of thermal treatment on the structure of multi-walled carbon nanotubes". Journal of Nanoparticle Research 8, 615-625 (2006).
22. F. Avilés, J. Cauich-Rodríguez, L. Moo-Tah, A. May-Pat, R. Vargas-Coronado, "Evaluation of mild acid oxidation treatments for MWCNT functionalization". Carbon 47, 2970-2975 (2009).
23. 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, 395-400 (1999).
24. C. Velasco-Santos, A.L. Martínez-Hernández, F.T. Fisher, R. Ruoff, V.M. Castano, "Improvement of thermal and mechanical properties of carbon nanotube composites through chemical functionalization". Chemistry of Materials 15, 4470-4475 (2003).
25. M.M.R. Nayini, S. Bastani, Z. Ranjbar, "Synthesis and characterization of functionalized carbon nanotubes with different wetting behaviors and their influence on the wetting properties of carbon nanotubes/polymethylmethacrylate coatings". Progress in Organic Coatings 77, 1007-1014 (2014).
26. D. Seo, W. Yoon, S. Park, M. Jo, J. Kim, "The preparation of multi-walled CNT-PMMA nanocomposite". Carbon letters 7, 266-270 (2006).
27. M. Annala, M. Lahelin, J. Seppälä, "Utilization of poly (methyl methacrylate)-carbon nanotube and polystyrene-carbon nanotube in situ polymerized composites as masterbatches for melt mixing". Express Polymer Letters 6, 814-825 (2012).
28. G.L. Hwang, Y.T. Shieh, K.C. Hwang, "Efficient load transfer to polymer‐grafted multiwalled carbon nanotubes in polymer composites". Advanced Functional Materials 14, 487-491 (2004).
29. M. Lahelin, A. Vesterinen, A. Nykänen, J. Ruokolainen, J. Seppälä, "In situ polymerization of methyl methacrylate/multi-walled carbon nanotube composites using cationic stearyl methacrylate copolymers as dispersants". European Polymer Journal 47, 873-881 (2011).
30. M. Li, X. Wang, R. Tian, F. Liu, H. Hu, R. Chen, H. Zheng, L. Wan, "Preparation, solubility, and electrorheological properties of carbon nanotubes/poly (methyl methacrylate) nanocomposites by in situ functionalization". Composites Part A: Applied Science and Manufacturing 40, 413-417 (2009).
31. N.G. Sahoo, S. Rana, J.W. Cho, L. Li, S.H. Chan, "Polymer nanocomposites based on functionalized carbon nanotubes". Progress in Polymer Science 35, 837-867 (2010).
32. K. Zhang, J. Lim, H. Choi, Y. Seo, "Core–shell structured carbon nanotube/poly (methyl methacrylate) composite and its electrorheological characteristics". Diamond and Related Materials 17, 1604-1607 (2008).
33. X. Yao, H. Wu, J. Wang, S. Qu, G. Chen, "Carbon nanotube/poly (methyl methacrylate)(CNT/PMMA) composite electrode fabricated by in situ polymerization for microchip capillary electrophoresis". Chemistry–A European Journal 13, 846-853 (2007).
34. D.Y. Wu, S. Meure, D. Solomon, "Self-healing polymeric materials: a review of recent developments". Progress in Polymer Science 33, 479-522 (2008).
35. C.B. Lin, S. Lee, K.S. Liu, "Methanol‐Induced crack healing in poly (methyl methacrylate)". Polymer Engineering & Science 30, 1399-1406 (1990).
36. R. Wool, K. O’connor, "A theory crack healing in polymers". Journal of Applied Physics 52, 5953-5963 (1981).
37. J.P. Harmon, S. Lee, J. Li, "Anisotropic methanol transport in PMMA after mechanical deformation". Polymer 29, 1221-1226 (1988).
38. N. Thomas, A. Windle, "Diffusion mechanics of the system PMMA-methanol". Polymer 22, 627-639 (1981).
39. G. Choudalakis, A. Gotsis, "Free volume and mass transport in polymer nanocomposites". Current Opinion in Colloid & Interface Science 17, 132-140 (2012).
40. T. Alfrey Jr, E. Gurnee, W. Lloyd, "Diffusion in glassy polymers". Journal of Polymer Science Part C: Polymer Symposia 12, 249-261 (1966).
41. L. Masaro, X. Zhu, "Physical models of diffusion for polymer solutions, gels and solids". Progress in Polymer Science 24, 731-775 (1999).
42. N.L. Thomas, A. Windle, "A theory of case II diffusion". Polymer 23, 529-542 (1982).
43. C.Y. Hui, K.C. Wu, R.C. Lasky, E.J. Kramer, "Case‐II diffusion in polymers. I. Transient swelling". Journal of Applied Physics 61, 5129-5136 (1987).
44. T. Mitsuoka, A. Torikai, K. Fueki, "Wavelength sensitivity of the photodegradation of poly (methyl methacrylate)". Journal of Applied Polymer Science 47, 1027-1032 (1993).
45. S. Eve, J. Mohr, "Effects of UV-irradiation on the thermo-mechanical properties of optical grade poly (methyl methacrylate)". Applied Surface Science 256, 2927-2933 (2010).
46. J. Yu, X. Tao, H. Tam, M.S. Demokan, "Modulation of refractive index and thickness of poly (methyl methacrylate) thin films with UV irradiation and heat treatment". Applied Surface Science 252, 1283-1292 (2005).
47. Y.F. Chuang, H.C. Wu, F. Yang, T.J. Yang, S. Lee, "Cracking and healing in poly (methyl methacrylate): effect of solvent". Journal of Polymer Research 24, 2 (2017).
48. M. Zhu, D. Vesely, "The effect of polymer swelling and resistance to flow on solvent diffusion and permeability". European Polymer Journal 43, 4503-4515 (2007).
49. H.-S. Kim, W.-I. Park, M. Kang, H.-J. Jin, "Multiple light scattering measurement and stability analysis of aqueous carbon nanotube dispersions". Journal of Physics and Chemistry of Solids 69, 1209-1212 (2008).
50. J. Choi, J. Moore, J. Corelli, J. Silverman, H. Bakhru, "Degradation of poly (methylmethacrylate) by deep ultraviolet, x‐ray, electron beam, and proton beam irradiations". Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena 6, 2286-2289 (1988).
51. A. Torikai, M. Ohno, K. Fueki, "Photodegradation of poly (methyl methacrylate) by monochromatic light: quantum yield, effect of wavelengths, and light intensity". Journal of Applied Polymer Science 41, 1023-1032 (1990).
52. M.-F. Chang, F. Yang, S. Lee, "Microhardness of poly (methyl methacrylate)-multiwalled carbon nanotubes composites: effect of ultraviolet irradiation". Materials Chemistry and Physics, (2018).
53. X. Lu, B. Jiang, "Glass transition temperature and molecular parameters of polymer". Polymer 32, 471-478 (1991).
54. K. Chee, "Dependence of glass transition temperature on chain flexibility and intermolecular interactions in polymers". Journal of Applied Polymer Science 43, 1205-1208 (1991).
55. L.P. Blanchard, J. Hesse, S.L. Malhotra, "Effect of molecular weight on glass transition by differential scanning calorimetry". Canadian Journal of Chemistry 52, 3170-3175 (1974).
56. A. Dazzi, A. Deniset-Besseau, P. Lasch, "Minimising contributions from scattering in infrared spectra by means of an integrating sphere". Analyst 138, 4191-4201 (2013).
57. J.M. O'Reilly, R. Mosher, "Conformational energies of stereoregular poly (methyl methacrylate) by Fourier transform infrared spectroscopy". Macromolecules 14, 602-608 (1981).
58. G. Socrates, Infrared and Raman characteristic group frequencies: tables and charts. John Wiley & Sons, Lodon, UK, 280-282.(2004),
59. D. Baskaran, J.W. Mays, M.S. Bratcher, "Polymer‐grafted multiwalled carbon nanotubes through surface‐initiated polymerization". Angewandte Chemie 116, 2190-2194 (2004).
60. M. Pantoja-Castro, J. Pérez-Robles, H. González-Rodríguez, Y. Vorobiev-Vasilievitch, H. Martínez-Tejada, C. Velasco-Santos, "Synthesis and investigation of PMMA films with homogeneously dispersed multiwalled carbon nanotubes". Materials Chemistry and Physics 140, 458-464 (2013).
61. A. Mueller, B. Vigolo, E. McRae, A.V. Soldatov, "Raman study of inhomogeneities in carbon nanotube distribution in CNT–PMMA composites". Physica Status Solidi (b) 247, 2810-2813 (2010).
62. J.P. Harmon, S. Lee, J. Li, "Methanol transport in PMMA: The effect of mechanical deformation". Journal of Polymer Science Part A: Polymer Chemistry 25, 3215-3229 (1987).
63. C. Yu, C. Lin, S. Lee, "Theory for the rate of crack closure". Journal of Applied Physics 78, 212-216 (1995).
64. X.L. Xie, Y.W. Mai, X.P. Zhou, "Dispersion and alignment of carbon nanotubes in polymer matrix: a review". Materials Science and Engineering: R: Reports 49, 89-112 (2005).
65. B. Arash, Q. Wang, V. Varadan, "Mechanical properties of carbon nanotube/polymer composites". Scientific Reports 4, 6479 (2014).
66. F. Yang, "Effect of UV-irradiation on mechanical properties of poly(methyl methacrylate)-multiwalled carbon nanotubes composites". Private Communication, (2018).
67. T. Caykara, O. Güven, "UV degradation of poly (methyl methacrylate) and its vinyltriethoxysilane containing copolymers". Polymer Degradation and Stability 65, 225-229 (1999).
68. C. Wochnowski, M.S. Eldin, S. Metev, "UV-laser-assisted degradation of poly (methyl methacrylate)". Polymer Degradation and Stability 89, 252-264 (2005).
69. G.C. Sih, Handbook of Stress-intensity Factors. Lehigh University, Institute of Fracture and Solid Mechanics, 1.2.4-1.(1973),
70. K. Jud, H. Kausch, "Load transfer through chain molecules after interpenetration at interfaces". Polymer Bulletin 1, 697-707 (1979).
71. K. Jud, H. Kausch, J. Williams, "Fracture mechanics studies of crack healing and welding of polymers". Journal of Materials Science 16, 204-210 (1981).
72. R. Wool, K. O'Connor, "Time dependence of crack healing". Journal of Polymer Science: Polymer Letters 20, 7-16 (1982).
73. A. Eatemadi, H. Daraee, H. Karimkhanloo, M. Kouhi, N. Zarghami, A. Akbarzadeh, M. Abasi, Y. Hanifehpour, S.W. Joo, "Carbon nanotubes: properties, synthesis, purification, and medical applications". Nanoscale Research Letters 9, 393 (2014).