بررسی حساسیت نانومادة مرکب نانولولة کربنی - اپوکسی در کرنش‌سنجی با استفاده از تغییرات مقاومت الکتریکی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری / دانشکدة مهندسی مکانیک، دانشگاه تهران

2 کارشناسی ارشد / دانشکدة مهندسی مواد و متالورژی، دانشگاه علم و صنعت ایران

3 دانشجوی دکتری / دانشکدة مهندسی برق و کامپیوتر، دانشگاه شهید بهشتی

چکیده

نانولوله‌های کربنی چندجداره، که در مواد پلیمری به‌کار می‌روند، با هدف ایجاد حسگر پیزو مقاومتی در پایش سلامت سازه‌های مهندسی استفاده می‌شوند. در این مقاله، حساسیت به تغییرات کرنش در نانومادة مرکب حاوی نانولوله کربنی - اپوکسی با استفاده از تغییرات الکتریکی بررسی شد. حسگر نانومادة مرکب روی یک تیر آلومنیمی یک‌سر گیردار چسبانده شده است تا اعمال کرنش روی آن ممکن باشد. ابتدا نانولوله‌های کربنی چندجداره با درصد‌های مختلف وزنی از 0/01 تا 1/5، درون زمینة اپوکسی به‌صورت نسبتاً یکنواخت توزیع شدند. این فرایند توسط یک همزن مکانیکی انجام شد. بدین‌ترتیب ماده‌ای هوشمند و مناسب برای سنجش کرنش ایجاد گردید. با استفاده از میکروسکوپ الکترونی ریزساختار این حسگر بررسی شد تا نحوة توزیع نانولوله‌های کربنی درون زمینة اپوکسی و تشکیل شبکة رسانا مشخص شود. اثر فرایند آماده‌سازی نانومادة مرکب بر تغییرات الکتریکی و کرنش، طی بارگذاری مکانیکی بررسی شد. نتایج نشان داد که اختلاط اولیة اپوکسی و سخت‌کننده منجر به حساسیت بیشتر حسگر نسبت به تغییرات الکتریکی شده است. همچنین آماده‌سازی نمونه‌ها با دو دمای پخت 80 و 100 درجة سانتی‌گراد نشان داد که نمونه‌های ساخته‌شده با دمای پخت پایین‌تر، حساسیت بیشتری نسبت به کرنش اعمال شده دارند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of the strain sensing sensitivity of the CNT-epoxy nanocomposite via changes in electrical resistance

نویسندگان [English]

  • Omid Sam Daliri 1
  • Azadeh Vatani 2
  • Ali Bozorgmehr 3
1 PhD candidate / Department of Mechanical Engineering, University of Tehran, Tehran
2 Graduated Student / Department of Metallurgy and Materials Engineering, Iran University of science and technology
3 PhD candidate / Department of computer science and Engineering, Shahid Beheshti University, Tehran
چکیده [English]

Multi-wall carbon nanotubes (MWCNTs) which are mixed in polymer materials could be used as a piezoresistive strain sensor for the purpose of structural health monitoring in engineering structures. In this paper, stain sensing sensitivity of CNT-epoxy nanocomposite is presented with changes in electrical resistance. Nanocomposite sensor is sticked on the aluminum cantilever beam to apply strain on it. Initially, MWCNTs with varying content from 0.01 wt% to 1.5 wt% were uniformly dispersed in the epoxy matrix. Dispersion process was conducted with shear mixing device. Therefore, a smart material was created, which was suitable for strain sensing. The microstructure of the sensor was evaluated using scanning electron microscopy to characterize typical distribution of the MWCNTs inside the epoxy matrix and form conductive networks. The effect of the preparation method (type of initial mixing, curing temperature and MWCNTs weight percent) studied on the strain and electrical changes during mechanical loading. The results showed that, initial mixing of epoxy and hardener resulted in higher sensitivity of electrical changes. Also, nanocomposite was more sensitive to strains in cantilever beam when filler content of nanocomposite was closed to the percolation threshold. In addition, sample preparation at various temperatures of 80 and 100 oc showed that the samples in lower curing temperature were more sensitive to the applied strain.

کلیدواژه‌ها [English]

  • carbon nanotubes (CNT)
  • Nanocomposite
  • electrical resistance changes
  • sensor

[1] J. Suhr, N. Koratkar, P. Keblinski, P. Ajayan, Viscoelasticity in carbon nanotube composites, Nature materials, Vol. 4, No. 2, pp. 134-137, 2005.

[2] F. Gojny, M. Wichmann, U. Köpke, B. Fiedler, K. Schulte, Carbon nanotube-reinforced epoxy-composites: enhanced stiffness and fracture toughness at low nanotube content, Composites Science and Technology, Vol. 64, No. 15, pp. 2363-2371, 2004.

[3] E. T. Thostenson, T. W. Chou, On the elastic properties of carbon nanotube-based composites: modelling and characterization, Journal of Physics D: Applied Physics, Vol. 36, No. 5, pp. 573, 2003.

[4] E. T. Thostenson, T. W. Chou, Aligned multi-walled carbon nanotube-reinforced composites: processing and mechanical characterization, Journal of physics D: Applied physics, Vol. 35, No. 16, pp. L77, 2002.

[5] F. Du, J. E. Fischer, K. I. Winey, Effect of nanotube alignment on percolation conductivity in carbon nanotube/polymer composites, Physical Review B, Vol. 72, No. 12, pp. 121404, 2005.

[6] B. Vigolo, C. Coulon, M. Maugey, C. Zakri, P. Poulin, An experimental approach to the percolation of sticky nanotubes, Science, Vol. 309, No. 5736, pp. 920-923, 2005.

[7] L. Wang, Z. M. Dang, Carbon nanotube composites with high dielectric constant at low percolation threshold, Applied physics letters, Vol. 87, No. 4, pp. 042903, 2005.

[8] J. Sandler, J. Kirk, I. Kinloch, M. Shaffer, A. Windle, Ultra-low electrical percolation threshold in carbon-nanotube-epoxy composites, Polymer, Vol. 44, No. 19, pp. 5893-5899, 2003.

[9] K. Schulte, C. Baron, Load and failure analyses of CFRP laminates by means of electrical resistivity measurements, Composites science and technology, Vol. 36, No. 1, pp. 63-76, 1989.

[10] B. M. Lee, S. Gupta, K. J. Loh, S. Nagarajaiah, Strain sensing and structural health monitoring using nanofilms and nanocomposites, Innovative Developments of Advanced Multifunctional Nanocomposites in Civil and Structural Engineering, pp. 303, 2016.

[11] D. D. Chung, Self-monitoring structural materials, Materials Science and Engineering: R: Reports, Vol. 22, No. 2, pp. 57-78, 1998.

[12] J. N. Coleman, U. Khan, W. J. Blau, Y. K. Gun’ko, Small but strong: a review of the mechanical properties of carbon nanotube–polymer composites, Carbon, 2006, Vol. 44, No. 9, pp. 1624-1652, 1998.

[13] D. J. Kwon, Z. J. Wang, J. Y. Choi, P. S. Shin, K. L. DeVries, J. M. Park, Damage sensing and fracture detection of CNT paste using electrical resistance measurements, Composites Part B: Engineering, Vol. 90, pp. 386-391, 2016.

[14] S. Mishra, K. Kumaran, R. Sivakumaran, S. P. Pandian, S. Kundu, Synthesis of PVDF/CNT and their functionalized composites for studying their electrical properties to analyze their applicability in actuation & sensing, Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 509, pp. 684-696, 2016.

[15] C. Li, E. T. Thostenson, T. W. Chou, Sensors and actuators based on carbon nanotubes and their composites: a review, Composites Science and Technology, Vol. 68, No. 6, pp. 1227-1249, 2008.

[16] E. T. Thostenson, T. W. Chou, Carbon nanotube networks: sensing of distributed strain and damage for life prediction and self healing, Advanced Materials, Vol. 18, No. 21, pp. 2837-2841, 2006.

[17] I. Alig, P. Pötschke, D. Lellinger, T. Skipa, S. Pegel, G. R. Kasaliwal, T. Villmow, Establishment, morphology and properties of carbon nanotube networks in polymer melts, Polymer, Vol. 53, No. 1, pp. 4-28, 2012.

[18] M. Moniruzzaman, K. I. Winey, Polymer nanocomposites containing carbon nanotubes, Macromolecules, Vol. 39, No. 16, pp. 5194-5205, 2006.

[19] L. Flandin, Y. Brechet, J. Y. Cavaille, Electrically conductive polymer nanocomposites as deformation sensors, Composites Science and Technology, Vol. 61, No. 6, pp. 895-901, 2001.

[20] R. Zhang, M. Baxendale, T. Peijs, Universal resistivity–strain dependence of carbon nanotube/polymer composites, Physical Review B, Vol. 76, No. 19, pp. 195433, 2007.

[21] M. Nofar, S. Hoa, M. Pugh, Failure detection and monitoring in polymer matrix composites subjected to static and dynamic loads using carbon nanotube networks, Composites Science and Technology, Vol. 69, No. 10, pp. 1599-1606, 2009.

[22] N. Hu, Y. Karube, C. Yan, Z. Masuda, H. Fukunaga, Tunneling effect in a polymer/carbon nanotube nanocomposite strain sensor, Acta Materialia, Vol. 56, No. 13, pp. 2929-2936, 2008.

[23] A. Ferrreira, J. Rocha, A. Ansón-Casaos, M. Martínez, F. Vaz, S. Lanceros-Mendez, Electromechanical performance of poly (vinylidene fluoride)/carbon nanotube composites for strain sensor applications, Sensors and Actuators A: Physical, Vol. 178, pp. 10-16, 2012.

[24] N. Hu, H. Fukunaga, S. Atobe, Y. Liu, J. Li, Piezoresistive strain sensors made from carbon nanotubes based polymer nanocomposites, Sensors, Vol. 11, No. 11, pp. 10691-10723, 2011.