DOI QR코드

DOI QR Code

Molecular Dynamics and Micromechanics Study on Mechanical Behavior and Interfacial Properties of BNNT/Polymer Nanocomposites

분자동역학 전산모사와 미시역학 모델을 이용한 질화붕소 나노튜브/고분자 복합재의 역학적 물성 및 계면특성 예측

  • Choi, Seoyeon (School of Energy Systems Engineering, Mechanical Engineering Division, Chung-Ang University) ;
  • Yang, Seunghwa (School of Energy Systems Engineering, Mechanical Engineering Division, Chung-Ang University)
  • Received : 2017.06.29
  • Accepted : 2017.08.31
  • Published : 2017.08.31

Abstract

In this study, the mechanical behavior and interface properties of boron nitride nanotube-poly(methyl methacrylate) nanocomposites are predicted using the molecular dynamics simulations and the double inclusion model. After modeling nanocomposite unit cell embedding single-walled nanotube and polymer, the stiffness matrix is determined from uniaxial tension and shear tests. Through the orientation average of the transversely isotropic stiffness matrix, the effective isotropic elastic constants of randomly dispersed microstructure of nanocomposites. Compared with the double inclusion model solution with a perfect interfacial condition, it is found that the interface between boron nitride nanotube and polymer matrix is weak in nature. To characterize the interphase surrounding the nanotube, the two step domain decomposition method incorporating a linear spring model at the interface is adopted. As a result, various combinations of the interfacial compliance and the interphase elastic constants are successfully determined from an inverse analysis.

본 연구에서는 분자동역학 전산모사와 이중 입자 모델을 이용하여 질화붕소 나노튜브-폴리메틸메타크릴레이트 나노복합재의 기계적 물성과 계면특성을 규명하였다. 단일 벽 나노튜브가 고분자 기지에 함침된 가로등방성 나노복합재 단위 셀 구조를 모델링한 후, 각 방향으로의 일축인장 및 전단 전산모사를 통해 나노복합재의 강성행렬을 예측하였다. 또한 강성행렬의 방향 평균을 취해 나노튜브가 기지 내에 랜덤 분포하는 경우의 등방성 탄성계수를 도출하였다. 분자동역학 해석 결과를 계면의 완전 결합을 가정한 이중 입자 모델 예측해와 비교한 결과, 질화붕소 나노튜브와 고분자 기지간의 계면이 불완전한 것으로 확인되었다. 나노튜브 주위에 형성되는 흡착계면의 물성을 예측하기 위해 2단계 영역 분할 기법을 도입하였고 계면의 불완전 결합을 선형 스프링으로 묘사하였다. 그 결과 다양한 스프링 컴플라이언스 값에 따른 흡착계면의 물성을 역 해석을 통해 확인할 수 있었다.

Keywords

References

  1. Chopra, N.G., Luyken, R.J., Cherrey, K., Crespi, V.H., Cohen, M.L., Louie, S.G., and Zettle, A., "Boron Nitride Nanotubes," Science, Vol. 269, No. 5226, 1995, pp. 966-967. https://doi.org/10.1126/science.269.5226.966
  2. Chang, C.W., Fennimore, A.M., Afanasiev, A., Okawa, D., Ikuno, T., Garcia, H., Li, D., Majumdar, A., and Zettle, A., "Isotope Effect on the Thermal Conductivity of Boron Nitride Nanotubes," Physical Review Letters, Vol. 97, 2006, 085901. https://doi.org/10.1103/PhysRevLett.97.085901
  3. Simard, B., "Industrialization of Boron Nitride Nanotubes: From Synthesis to Applications," Proceeding of TechConnect World Innovation, Washington DC, US, Jun. 2014.
  4. Cohen, M.L., and Zettle, A., "The Physics of Boron Nitride Nanotubes," Physics Today, Vol. 63, No. 11, 2010, pp. 34-38. https://doi.org/10.1063/1.3518210
  5. Yuan, J., and Liew, K.M., "Effects of Boron Nitride Impurities on the Elastic Properties of Carbon Nanotubes," Nanotechnology, Vol. 19, 2008, 445703. https://doi.org/10.1088/0957-4484/19/44/445703
  6. Verma, V., Jindal, V.K., and Dharamvir, K., "Elastic Moduli of a Boron Nitride Nanotube," Nanotechnology, Vol. 18, 2007, 435711. https://doi.org/10.1088/0957-4484/18/43/435711
  7. Jin, J., and Yang, S., "Molecular Dynamics Study on Mechanical Behavior and Load Transfer of CNT/PET Nanocomposites : the Effects of Covalent Grafting," Composites Research, Under Review, 2017.
  8. Rappe, A.K., and GoddardIII, W.A., "Charge Equilibration for Molecular Dynamics Simulations," Journal of Physical Chemistry, Vol. 95, No. 8, 1991, pp. 3358-3363. https://doi.org/10.1021/j100161a070
  9. Hoover, W.G., "Canonical Dynamics: Equilibrium Phase-space Distributions," Physical Review A, Vol. 31, 1985, pp. 1695-1697. https://doi.org/10.1103/PhysRevA.31.1695
  10. Hoover, W.G., "Constant-pressure Equations of Motion," Physical Review A, Vol. 34, 1986, pp. 2499-2500. https://doi.org/10.1103/PhysRevA.34.2499
  11. Yang, S., Yu, S., Kyoung, W., Hahn, D.S., and Cho, M., "Multiscale Modeling of Size-dependent Elastic Properties of Carbon Nanotube/polymer Nanocomposites with Interfacial Imperfections," Polymer, Vol. 5, No. 2, 2012, pp. 623-633.
  12. Hori, M., and Nemat-Nasser, S., "Double-Inclusion Model and Overall Moduli of Multi-Phase Composites," Mechanical of Materials, Vol. 14, 1993, pp. 189-206. https://doi.org/10.1016/0167-6636(93)90066-Z
  13. Li, J.Y., "Thermoelastic Behavior of Composites With Functionally Graded Interphase: a Multi-Inclusion Model," International Journal of Solids and Structures, Vol. 37, 2000, pp. 5579-5597. https://doi.org/10.1016/S0020-7683(99)00227-9
  14. Qu, J., "Eshelby Tensor for an Elastic Inclusion with Slightly Weakened Interface," Journal of Applied Mechanics, Vol. 60, No. 4, 1993, pp. 1048-1050. https://doi.org/10.1115/1.2900974
  15. Hu, G.K., and Weng, G.J., "The Connections Between the Double-Iinclusion Model and the Ponte Castaneda-Wills, Mori- Tanaka, and Kuster-Toksoz Models," Mechanics of Materials, Vol. 32, 2000, pp. 495-503. https://doi.org/10.1016/S0167-6636(00)00015-6
  16. Yang, S., Yu, S., Ryu, J., Cho, J.M., Kyoung, W., Han, D.S., and Cho, M., "Nonlinear Multiscale Modeling Approach to Characterize Elastoplastic Behavior of CNT/Polymer Nanocomposites Considering the Interphase and Interfacial Imperfection," International Journal of Plasticity, Vol. 41, 2013, pp. 124-146. https://doi.org/10.1016/j.ijplas.2012.09.010
  17. Yang, S., and Cho, M., "Scale Bridging Method to Characterize Mechanical Properties of Nanoparticle/Polymer Nanocomposites," Applied Physics Letters, Vol. 93, No. 4, 2008, 043111. https://doi.org/10.1063/1.2965486