Utilizing ammonium persulfate assisted expansion to fabricate flexible expanded graphite films with excellent thermal conductivity by introducing wrinkles

Carbon ◽  
2019 ◽  
Vol 153 ◽  
pp. 565-574 ◽  
Author(s):  
Yuhang Liu ◽  
Bingxin Qu ◽  
Xunen Wu ◽  
Yuxin Tian ◽  
Kai Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Expanded Graphite ◽  
Ammonium Persulfate

A new way synthesis of expanded graphite as a thermal filler to enhance the thermal conductivity of DGEBA resin as thermal interface material

2019 ◽  
Vol 32 (5) ◽  
pp. 506-523 ◽  
Author(s):  
Sagar Kumar Nayak ◽  
Smita Mohanty ◽  
Sanjay K Nayak
Keyword(s):  
Thermal Conductivity ◽  
Composite System ◽  
Expanded Graphite ◽  
Ammonium Persulfate ◽  
Stir Casting ◽  
Thermal Interface Material ◽  
Step Method ◽  
Thermal Interface ◽  
Lap Shear ◽  
Uniform Dispersion

In this work, a facile two-step method for the synthesis of highly thermal conductive expanded graphite (EG) was proposed. A binary component system of ammonium persulfate and concentrated sulfuric acid was prepared for the synthesis of EG from natural graphite flakes in which the former one acted as an oxidizing agent and the latter one used as an intercalating agent. Further, the silane functionalization of EG (mEG) was purposefully completed, as confirmed from the X-ray diffraction and Fourier transform infrared spectroscopy analysis. Epoxy-based thermal interface materials (TIMs) were fabricated with reinforcing EG and mEG by stir-casting method at different filler fraction. The guarded heat flow meter method indicated that the enhancement in thermal conductivity (TC) was 12.12-fold at 10 wt% loading of mEG (mEG10-Ep) than neat epoxy. The binding strength of mEG10-Ep composite tuned to 6.18 ± 0.8 MPa and determined by a single lap shear test, which confirms better reinforcing effect of silane functionalized EG than neat EG counterpart. The same was also corroborated from porosity evaluation of the composite system. At 50% weight loss in nitrogen atmosphere, thermogravimetric analysis revealed that the composite was stable up to 430°C. Dynamic mechanical analysis was engaged to estimate the glass transition temperature ( T g) of the epoxy composite system, which validates its prospective application as preferred TIMs in the electroactive device. The electrical conductivity of composite was deteriorated due to the encapsulation of EG with nonconductive silane functional groups. The uniform dispersion was achieved by mEG-filled composite as compared to its EG counterpart, which was visualized from fracture surface through scanning electron microscopy.

Improvement in thermal conductivity and mechanical properties of ethylene-propylene-diene monomer rubber by expanded graphite

2015 ◽  
Vol 38 (5) ◽  
pp. 870-876 ◽  
Author(s):  
Shaojian He ◽  
Yankai Lin ◽  
Lin Chen ◽  
Shanqiao Cao ◽  
Jun Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Expanded Graphite ◽  
Ethylene Propylene Diene Monomer ◽  
Ethylene Propylene

Two-different ways of synthesis for EG: Study of mechanical, thermal, and electrical properties of epoxy composite for TIMs

2020 ◽  
pp. 095400832094538
Author(s):  
Sagar Kumar Nayak ◽  
Arjyama Mishra ◽  
Subhransu S Pradhan ◽  
Jyoti Agarwal
Keyword(s):  
Electron Microscopy ◽  
Epoxy Composite ◽  
Expanded Graphite ◽  
Ammonium Persulfate ◽  
Zinc Nitrate ◽  
Electrochemical Process ◽  
Graphite Flake ◽  
Nitrate Hexahydrate ◽  
Transmission Electron ◽  
Inverse Rule

The current study reports the synthesis of expanded graphite (EG) in two different ways and its fabrication with epoxy matrix to form composite at various filler fractions (5, 10, 12.5). One type EG (EG-C) is prepared by the electrochemical process using natural graphite flake (NGF), concentrated sulfuric acid, and ammonium persulfate, while the other (EG-P) is just mixing and heating of NGF with zinc nitrate hexahydrate. The functional groups of synthesized EG were confirmed by Fourier transform infrared spectroscopy. The surface morphology and microstructure of synthesized filler (EG-C, EG-P) were studied using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. An optimum through-plane thermal conductivity (TC) of 2.04 and 2.22 W/mK was observed in the case of the composites containing 12.5 wt% of EG-C and EG-P, respectively. The obtained experimental TC was compared with three numerical thermal models, that is, inverse rule of mixture, Maxwell–Eucken model, and Agari model. Furthermore, the thermal stability of both composites was compared by using a thermogravimetric analyzer. The electrical resistivity of EG-P/epoxy composite at different formulations was higher than the EG-C-filled epoxy composites.

Intercalation of copper microparticles in an expanded graphite film with improved through-plane thermal conductivity

2020 ◽  
Vol 55 (17) ◽  
pp. 7351-7358
Author(s):  
Jing xia ◽  
Junqing Liu ◽  
Dongfang Zheng ◽  
Chunting Duan ◽  
Bo Feng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Expanded Graphite ◽  
Graphite Film

scholarly journals Copper Metallic Powder Effect for Expanded Graphite Plate for Thermal Conductivity

2017 ◽  
Vol 29 (10) ◽  
pp. 2154-2158 ◽  
Author(s):  
Dinh Cung Tien Nguyen ◽  
Biswas Md Rokon Dowla ◽  
Yonrapach Areerob ◽  
Asghar Ali ◽  
Won-Chun Oh
Keyword(s):  
Thermal Conductivity ◽  
Expanded Graphite ◽  
Metallic Powder ◽  
Graphite Plate

Effect of the Additive on Thermal Conductivity of the Phase Change Material

2011 ◽  
Vol 399-401 ◽  
pp. 1302-1306 ◽  
Author(s):  
Wei Hua Li ◽  
Jin Feng Mao ◽  
Li Jun Wang ◽  
Lu Yan Sui
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Material ◽  
Sodium Acetate ◽  
Heat Storage ◽  
Expanded Graphite ◽  
Sodium Acetate Trihydrate ◽  
Acetate Trihydrate ◽  
Composite Phase Change Material ◽  
Change Material

The aim of the paper is to analyze the effect of the additives on thermal conductivity of the phase change material. The experiment about heat storage and heat release performance of the composite phase change material which uses sodium acetate trihydrate as host material is studied. The effect of the expanded graphite on the composite phase change material is investigated. The results show that: expanded graphite which can be dispersed evenly in the composite phase change material, the thermal stability is well, significantly improve the thermal conductivity of the composite phase change material.

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