scholarly journals RGO-Coated Polyurethane Foam/Segmented Polyurethane Composites as Solid–Solid Phase Change Thermal Interface Material

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3004
Author(s):  
Cong Zhang ◽  
Zhe Shi ◽  
An Li ◽  
Yang-Fei Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
High Performance ◽  
In Situ Polymerization ◽  
Solid Phase ◽  
Thermal Interface Material ◽  
Segmented Polyurethane ◽  
Thermal Interface ◽  
Self Assembling

Thermal interface material (TIM) is crucial for heat transfer from a heat source to a heat sink. A high-performance thermal interface material with solid–solid phase change properties was prepared to improve both thermal conductivity and interfacial wettability by using reduced graphene oxide (rGO)-coated polyurethane (PU) foam as a filler, and segmented polyurethane (SPU) as a matrix. The rGO-coated foam (rGOF) was fabricated by a self-assembling method and the SPU was synthesized by an in situ polymerization method. The pure SPU and rGOF/SPU composite exhibited obvious solid–solid phase change properties with proper phase change temperature, high latent heat, good wettability, and no leakage. It was found that the SPU had better heat transfer performance than the PU without phase change properties in a practical application as a TIM, while the thermal conductivity of the rGOF/SPU composite was 63% higher than that of the pure SPU at an ultra-low rGO content of 0.8 wt.%, showing great potential for thermal management.

Thermal Contact Resistance of Phase Change and Grease Type Polymeric Materials

2000 ◽  
Author(s):  
Ravi S. Prasher ◽  
Craig Simmons ◽  
Gary Solbrekken
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Phase Change ◽  
High Performance ◽  
Phase Change Materials ◽  
Thermal Contact ◽  
Polymeric Materials ◽  
Thermal Interface Material ◽  
Heat Spreader ◽  
Thermal Grease

Abstract Thermal interface material (TIM) between the die and the heat spreader or between the heat spreader and the heat sink in any electronic package plays a very important role in the thermal management of electronic cooling. Due to increased power and power density high-performance TIMs are sought every day. Phase change materials (PCM) seem to be very good alternative to traditionally used thermal greases because of various reasons. These phase change materials also have the advantage of being reworked easily without damaging the die. Typically these phase change materials are polymer based and are particle laden to enhance their thermal conductivity. The thermal conductivity of these materials is relatively well understood than their contact resistance. Current work focuses on explicitly measuring the contact resistance and the thermal conductivity of a particular phase change TIM and some silicon-based greases. Effect of various parameters, which can affect the contact resistance of theses TIMs and Greases, are also captured. The steady state measurements of the thermal conductivity and the contact resistance was done on an interface tester. In general the work on the contact resistance of fluid-like polymer based TIM, such as thermal grease or phase change polymer has been experimental in the past. A semi-analytical model, which captures the various parameters affecting the contact resistance of two class of materials; the phase change and the thermal grease is also developed in this paper. This model fits very well with the experimental data.

Analytical Model of Heat Conduction in a Tubular Geometry With Application to a Nano-Structured Thermal Interface

2005 ◽  
Author(s):  
Anand Desai ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Thermal Conductivity ◽  
Power Dissipation ◽  
High Performance ◽  
Analytical Study ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Inner Diameter ◽  
Parametric Analyses ◽  
Interface Materials

Power dissipation in electronic devices is projected to increase significantly over the next ten years to the range of 50-150 Watts per cm2 for high performance applications [1]. This increase in power represents a major challenge to systems integration since the maximum device temperature needs to be around 100 C. One of the primary obstacles to the thermal management of devices operating at such high powers is the thermal resistance between the device and the heat spreader or heat sink that it is attached to. Typically the in situ thermal conductivity of interface materials is in the range of 1 to 4 W/mK, even though the bulk thermal conductivity of the material may be significantly higher. In order to improve the effective in-situ thermal conductivity of interface materials nanotubes are being considered as a possible addition to such interfaces. The primary approach taken in the current study is to analyze the enhancement of the thermal interface by adding carbon nano tubular cylinders that are oriented in the direction of transport. This paper presents the results of an analytical study of transport in a thermal interface material that is enhanced with carbon nanotubes. A variety of parametric analyses are carried out, such as by varying the inner diameter of the nanotube and the power dissipation, and the effect on spreading resistance is calculated. The results indicate that for high thermal conductivity nanotubes there is a significant increase in the effective thermal conductivity of the thermal interface material.

A Numerical Study of Transport in a Thermal Interface Material Enhanced With Carbon Nanotubes

2005 ◽  
Vol 128 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Anand Desai ◽  
Sanket Mahajan ◽  
Ganesh Subbarayan ◽  
Wayne Jones ◽  
James Geer ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
High Performance ◽  
Numerical Study ◽  
Temperature Drop ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
The Impact ◽  
Interface Materials

Power dissipation in electronic devices is projected to increase over the next 10years to the range of 150-250W per chip for high performance applications. One of the primary obstacles to the thermal management of devices operating at such high powers is the thermal resistance between the device and the heat spreader or heat sink that it is attached to. Typically the in situ thermal conductivity of interface materials is in the range of 1-4W∕mK, even though the bulk thermal conductivity of the material may be significantly higher. In an attempt to improve the effective in situ thermal conductivity of interface materials nanoparticles and nanotubes are being considered as a possible addition to such interfaces. This paper presents the results of a numerical study of transport in a thermal interface material that is enhanced with carbon nanotubes. The results from the numerical solution are in excellent agreement with an analytical model (Desai, A., Geer, J., and Sammakia, B., “Models of Steady Heat Conduction in Multiple Cylindrical Domains,” J. Electron. Packaging (to be published)) of the same geometry. Wide ranges of parametric studies were conducted to examine the effects of the thermal conductivity of the different materials, the geometry, and the size of the nanotubes. An estimate of the effective thermal conductivity of the carbon nanotubes was used, obtained from a molecular dynamics analysis (Mahajan, S., Subbarayan, G., Sammakia, B. G., and Jones, W., 2003, Proceedings of the 2003 ASME International Mechanical Engineering Congress and Exposition, Washington, D.C., Nov. 15–21). The numerical analysis was used to estimate the impact of imperfections in the nanotubes upon the overall system performance. Overall the nanotubes are found to significantly improve the thermal performance of the thermal interface material. The results show that varying the diameter of the nanotube and the percentage of area occupied by the nanotubes does not have any significant effect on the total temperature drop.

scholarly journals An Integrated Approach to Design and Develop High-Performance Polymer-Composite Thermal Interface Material

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 807
Author(s):  
Syed Sohail Akhtar
Keyword(s):  
Thermal Conductivity ◽  
Aspect Ratio ◽  
High Performance ◽  
High Thermal Conductivity ◽  
Thermal Interface Material ◽  
Design Stage ◽  
Filler Concentration ◽  
Melt Mixing ◽  
Thermal Interface ◽  
Wide Range

A computational framework based on novel differential effective medium approximation and mean-field homogenization is used to design high-performance filler-laden polymer thermal interface materials (TIMs). The proposed design strategy has the capability to handle non-dilute filler concentration in the polymer matrix. The effective thermal conductivity of intended thermal interface composites can be tailored in a wide range by varying filler attributes such as size, aspect ratio, orientation, as well as filler–matrix interface with an upper limit imposed by the shear modulus. Serval potential polymers and fillers are considered at the design stage. High-density polyethylene (HDPE) and thermoplastic polyurethane (TPU) with a non-dilute concentration (~60 vol%) of ceramic fillers exhibit high thermal conductivity (4–5 W m−1 K−1) without compromising the high compliance of TIMs. The predicted thermal conductivity and coefficient of thermal expansion are in excellent agreement with measured data of various binary composite systems considering HDPE, TPU, and polypropylene (PP) loaded with Al2O3 and AlN fillers in varying sizes, shapes, and concentrations, prepared via the melt-mixing and compression-molding route. The model also validates that manipulating filler alignment and aspect ratio can significantly contribute to making heat-conducting networks in composites, which results in ultra-high thermal conductivity.

scholarly journals Synthesis of Nitrogen-Doped Graphene on Copper Nanowires for Efficient Thermal Conductivity and Stability by Using Conventional Thermal Chemical Vapor Deposition

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 984 ◽  
Author(s):  
Minjeong Park ◽  
Seul-Ki Ahn ◽  
Sookhyun Hwang ◽  
Seongjun Park ◽  
Seonpil Kim ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Growth Temperature ◽  
Electronic Devices ◽  
Oxidation Stability ◽  
Thermal Interface Material ◽  
Amine Group ◽  
Thermal Interface ◽  
Aspect Ratios ◽  
Doped Graphene

Cu nanowires (NWs) possess remarkable potential a slow-cost heat transfer material in modern electronic devices. However, Cu NWs with high aspect ratios undergo surface oxidation, resulting in performance degradation. A growth temperature of approximately <1000 °C is required for preventing the changing of Cu NW morphology by the melting of Cu NWs at over 1000 °C. In addition, nitrogen (N)-doped carbon materials coated on Cu NWs need the formation hindrance of oxides and high thermal conductivity of Cu NWs. Therefore, we investigated the N-doped graphene-coated Cu NWs (NG/Cu NWs) to enhance both the thermal conductivity and oxidation stability of Cu NWs. The Cu NWs were synthesized through an aqueous method, and ethylenediamine with an amine group induced the isotropic growth of Cu to produce Cu NWs. At that time, the amine group could be used as a growth source for the N-doped graphene on Cu NWs. To grow an N-doped graphene without changing the morphology of Cu NWs, we report a double-zone growth process at a low growth temperature of approximately 600 °C. Thermal-interface material measurements were conducted on the NG/Cu NWs to confirm their applicability as heat transfer materials. Our results show that the synthesis technology of N-doped graphene on Cu NWs could promote future research and applications of thermal interface materials in air-stable flexible electronic devices.

Very High Performance Thermal Interface Material and Attachment Technology

2003 ◽  
Author(s):  
Ralph L. Webb ◽  
Jin Wook Paek ◽  
David Pickrell
Keyword(s):  
Thermal Conductivity ◽  
Thermal Degradation ◽  
Contact Resistance ◽  
High Performance ◽  
Copper Substrate ◽  
Alloy Layer ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Penn State

This paper provides an update on work at Penn State University on advanced thermal interface material (TIM) and attachment technology. The TIM concept consists of a “Low Melting Temperature Alloy” (LMTA) bonded to a thin copper substrate. The present work includes analytical modeling to separate the interface resistance (Rint) into “material” and “contact” resistance. Modeling indicates that contact resistance accounts for 1/3 of the interface resistance (Rint). Additional alloys have been identified that have thermal conductivity approximately three-times those identified in the previous 2002 publication. Thermal degradation of the LMTA TIM was also observed in the present work after extended thermal cycling above the melting point of the alloy. Possible mechanisms for this degradation are oxidation and contamination of the alloy layer rather than the inter-metallic diffusion. Use of the high thermal conductivity alloys, and soldered contact surfaces will provide very low Rint as well as minimizing the thermal degradation. It appears that Rint as small as, or less than, 0.005 cm2-K/W may be possible. Description of the modified Penn State TIM tester is provided, which will allow measurement of Rint = 0.01 cm2-K/W with less than 30% error.

scholarly journals Passive Thermal Management of Launch Vehicle Systems using Phase Changing Materials

2018 ◽  
Vol 68 (4) ◽  
pp. 337 ◽  
Author(s):  
Vijay Kumar Sen ◽  
Janmejay Jaiswal ◽  
Amarnath Nandi ◽  
Aliyas Areeckal Varkey ◽  
Aravindakshan Pillai
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Heat Sink ◽  
Solid Phase ◽  
Traditional Approach ◽  
Thermal Inertia ◽  
Reduction Factor ◽  
Launch Vehicles ◽  
Mass Reduction

<p>Electronic systems in expendable launch vehicles and missiles rely on their own thermal inertia to operate for the stipulated time, without overheating, owing to absence of active cooling systems and natural convection at elevated altitude. Traditionally, this inertia is built-into the electronics by increasing its chassis (support structure) mass, proportional to the associated thermal load. For power intensive systems, especially in vehicle upper stages where mass is at premium, this approach results in reduction in payload capability. In the proposed paper, a Heat Sink based on Neopentyl Glycol (NPG) with solid-to-solid phase change (crystalline transformation) is explored as a mass effective alternative due to the material’s capability to absorb a significant amount of energy during phase change. However, due to its lower thermal conductivity, a Thermal Conductivity Enhancer (TCE) to maximize heat transfer had to be employed. The resulting heat sink, utilizing TCE for heat transfer capability and NPG for heat storage capability is called as Hybrid Heat Sink. A heat sink with plate type fins as TCE is realized and a mass reduction factor of 1.4 is achieved against traditional approach. This is followed by a heat sink with pin type fins as TCE where mass reduction factor is increased to 2.6. Effect of thermal cycling and vibration on its performance is also studied.</p>

Heat Conduction Across Corrugated Thermal Interface

2007 ◽  
Author(s):  
Bozhi Yang ◽  
Wenjun Liu
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Analytical Solution ◽  
High Performance ◽  
Fem Simulation ◽  
Expansion Method ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Eigenfunction Expansion Method ◽  
First Time

This paper presents the analytical solution of the heat conduction across a corrugated thermal interface material with rectangular straight fin arrangement. Domain decomposition and eigenfunction expansion method were used to study the thermal diffusion in such geometry for the first time. The temperature field solved from the analytical method agrees well with FEM simulation. The total heat transfer rate across the corrugated interface and thermal boundary resistance were derived analytically also. Results have shown that the effective thermal resistance across the interface can be significantly reduced with the corrugated TIM geometry. The analytical solution in the paper can provide insight into geometry effect on the heat transfer enhancement, and is a very useful complement to experimental work and numerical simulation in designing high-performance corrugated thermal interface.

Development of a High Performance Thermal Interface Material With Vertically Aligned Graphite Platelets

2011 ◽  
Author(s):  
Y. Zhao ◽  
D. Strauss ◽  
T. Liao ◽  
Y. C. Chen ◽  
C. L. Chen
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
High Performance ◽  
Experimental Tests ◽  
Thermal Interface Material ◽  
Graphite Nanoplatelets ◽  
Compression Pressure ◽  
Thermal Interface ◽  
Soldering Process ◽  
Vertically Aligned

This paper introduces a high performance thermal interface material (TIM) with vertically aligned graphite. The main structure of the TIM is a vertically laminated structure, in which thin solder layers are laminated with aligned graphite layers. Unlike traditional TIMs infiltrated with randomly oriented high conductive fillers, the laminated TIM with vertically aligned graphite provides extraordinarily high z-axis thermal conductivity and controllable stiffness by simply setting the thickness of each component layer to match different surfaces. Thus, this design greatly improves the overall heat transfer performance. In addition, using metallic-graphite composites greatly improves the bonding between the graphite and the metallic host compared to nonmetallic materials, and thus the thermal boundary resistance can be significantly reduced. Moreover, compared to organic hosts, solders have much smaller phonon spectra mismatch with graphite nanoplatelets (GNPs), and thus offer significantly higher interface conductance. Furthermore, vertically connected solder layers can also lock the graphite layers in place and reinforce the strength of the entire package. A series of experimental tests was conducted to evaluate the effects of processing pressure and surface roughness on the overall thermal performance of the graphite TIMs. The results indicated that the overall thermal resistance of two smooth surfaces soldered by a 200 μm-thick graphite TIM was reduced from 0.12 to 0.03 cm2•K/W when the compression pressure applied during the soldering process was increased from 7 to 68 psi. Increased surface roughness appeared to improve heat transfer across the interface by enlarging the contact areas between the surface and the graphite TIMs. A preliminary numerical simulation verified this trend.

Optimization of thermal conductivity in composites loaded with the solid-solid phase-change materials

2018 ◽  
Vol 25 (6) ◽  
pp. 1157-1165
Author(s):  
Taoufik Mnasri ◽  
Adel Abbessi ◽  
Rached Ben Younes ◽  
Atef Mazioud
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Spherical Inclusions ◽  
First Case ◽  
The Matrix ◽  
Composite Conductivity ◽  
First Time

AbstractThis work focuses on identifying the thermal conductivity of composites loaded with phase-change materials (PCMs). Three configurations are studied: (1) the PCMs are divided into identical spherical inclusions arranged in one plane, (2) the PCMs are inserted into the matrix as a plate on the level of the same plane of arrangement, and (3) the PCMs are divided into identical spherical inclusions arranged periodically in the whole matrix. The percentage PCM/matrix is fixed for all cases. A comparison among the various situations is made for the first time, thus providing a new idea on how to insert PCMs into composite matrices. The results show that the composite conductivity is the most important consideration in the first case, precisely when the arrangement plane is parallel with the flux and diagonal to the entry face. In the present work, we are interested in exploring the solid-solid PCMs. The PCM polyurethane and a wood matrix are particularly studied.

Sign in / Sign up

Export Citation Format

Share Document