Improving thermal conductivity of epoxy resin by filling boron nitride nanomaterials: A molecular dynamics investigation

2019 ◽  
Vol 164 ◽  
pp. 108-115 ◽  
Author(s):  
Mingxiao Zhu ◽  
Jiacai Li ◽  
Jiming Chen ◽  
Henggao Song ◽  
Hongyu Zhang
2019 ◽  
Vol 54 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Sumit Sharma ◽  
Prince Setia ◽  
Rakesh Chandra ◽  
Nitin Thakur

Heat dissipation is very essential for the efficient working of electronic devices. There is a widespread demand for high thermal conductivity materials. Boron nitride nanotubes have high thermal conductivity but due to their poor interfacial adhesion with polymers, their use as heat dissipating material is restricted. In this study, a silane-coupling agent has been used to modify the boron nitride nanotubes. These tubes were then inserted in polymethyl methacrylate matrix. Various properties such as thermal conductivity, storage modulus, and loss factor have been predicted. Molecular dynamics simulations have also been used for accurate prediction of the properties of boron nitride nanotubes/polymethyl methacrylate composites. The boron nitride nanotubes weight percentage was varied from 0% to 70% for studying the effect on thermal conductivity, storage modulus, and loss factor. The experimentally obtained thermal conductivity increased rapidly from 0.6 W/mK at 40 wt.% of boron nitride nanotubes to about 3.8 W/mK at 80 wt.% of boron nitride nanotubes in polymethyl methacrylate matrix (an increase of nearly 533%). A similar trend was obtained using molecular dynamics simulations. The storage modulus increased from 2 GPa (for pure polymethyl methacrylate) to about 5 GPa (for 70 wt.% boron nitride nanotubes). The glass transition temperature of boron nitride nanotubes/polymethyl methacrylate composites shifted to higher temperatures with an increase in boron nitride nanotubes weight percentage.


2019 ◽  
Vol 40 (S2) ◽  
pp. E1600-E1611 ◽  
Author(s):  
Yulan Guo ◽  
Jing He ◽  
Hua Wang ◽  
Zheng Su ◽  
Qiqi Qu ◽  
...  

2011 ◽  
Vol 23 (6) ◽  
pp. 1025-1028 ◽  
Author(s):  
Junwei Gu ◽  
Qiuyu Zhang ◽  
Jing Dang ◽  
Chao Xie

Author(s):  
K. Raji ◽  
C. B. Sobhan ◽  
Jaime Taha-Tijerina ◽  
T. N. Narayanan ◽  
P. M. Ajayan

In applications such as coolants in electrical devices, in addition to high heat transfer capabilities, the cooling fluids are required to have low electrical conductivity also. As nanoparticle suspensions (nanofluids) show excellent thermal performance due to enhanced thermal conductivity, it would be advantageous to evolve nanofluid-coolants, which are electrically insulating also, for such applications. A theoretical analysis of one such suspension is performed in the present work, to evaluate the thermal conductivity enhancement due to the presence of nanoparticles in the base fluid. The nanofluid analyzed is a suspension of hexagonal boron nitride (h-BN) in mineral oil, for application as a cooling fluid in electrical transformers. The thermal conductivity of the boron nitride suspension is computed using equilibrium Molecular Dynamics (MD) simulations followed by the application of the Green-Kubo auto correlation function. The Lennard–Jones potentials and simple harmonic oscillation potentials are used as the intermolecular potentials to appropriately describe the various atomic and molecular interactions in the boron nitride suspension. The molecular dynamics simulations are performed using LAMMPS software. The computational results are benchmarked with experimental findings on the thermal conductivity enhancement in the suspension at various temperatures and concentrations of nanoparticles, obtained using a transient measurement technique.


2021 ◽  
pp. 095400832110323
Author(s):  
Jianwen Zhang ◽  
Dongwei Wang ◽  
Lujia Wang ◽  
Wanwan Zuo ◽  
Xiaohua Ma ◽  
...  

In this article, pure epoxy resin and silica–epoxy nanocomposite models were established to investigate the effects of hyperbranched polyester on microstructure and thermomechanical properties of epoxy resin through molecular dynamics simulation. Results revealed that the composite of silica can improve the thermomechanical properties of nanocomposites, including the glass transition temperature, thermal conductivity, and elastic modulus. Moreover, the thermomechanical properties were further enhanced through chemical modification on the silica surface, where the effectiveness was the best through grafting hyperbranched polyester on the silica surface. Compared with pure epoxy resin, the glass transition temperature of silica–epoxy composite modified by silica grafted with hyperbranched polyester increased by 38 K. The thermal conductivity increased with the increase of temperature and thermal conductivity at room temperature increased to 0.4171 W/(m·K)−1 with an increase ratio of 94.3%. Young’s modulus, volume modulus, and shear modulus all fluctuated as temperature rise with a down overall trend. They increased by 44.68%, 29.52%, and 36.65%, respectively, when compared with pure epoxy resin. At the same time, the thermomechanical properties were closely related to the microstructure such as fractional free volume (FFV), mean square displacement (MSD), and binding energy. Silica surface modification by grafting hyperbranched polyester reduced the FFV value and MSD value most and strengthened the combination of silica and epoxy resin matrix the best, resulting in the best thermomechanical properties.


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