scholarly journals High thermal conductivity polymer chains with reactive groups: a step towards true application

2020 ◽  
Vol 1 (6) ◽  
pp. 1996-2002
Author(s):  
Anqi Chen ◽  
Yanyan Wu ◽  
Shaoxin Zhou ◽  
Wenxue Xu ◽  
Wenlong Jiang ◽  
...  

Nanostructured polyethylene (PE, [–CH2–CH2–]n) films with metal-like thermal conductivity have opened up opportunities for polymers in advanced thermal management.

Author(s):  
Sally A. McMenamin ◽  
Annie Weathers ◽  
Virendra Singh ◽  
Michael T. Pettes ◽  
Baratunde A. Cola ◽  
...  

High thermal conductivity, comparable to that of a metal, has been observed in some stretched polyethylene nanofibers due to a decrease in defect density with the alignment of the polymer chains. Such high thermal conductivity may be useful for thermal management applications such as thermal adhesives made of aligned nanofibers. Polythiophene (Pth) is a conducting polymer that can be synthesized electrochemically as aligned nanofiber forests without the need for stretching individual fibers. Here we report the thermal conductivity of individual suspended Pth nanofibers synthesized electrochemically and measured with the use of a microfabricated device in the temperature range of 80 K to 375 K. The measured thermal conductivity increases with temperature. For three single suspended Pth nanofibers with a diameter on the order of 200 nm, the room temperature value between 0.6 and 0.8 W/m K is about four-fold higher than that reported for Pth thin films and comparable to that reported for binder-filler thermal adhesives.


Author(s):  
S. Ganguli ◽  
A. K. Roy ◽  
R. Wheeler

Carbon foam is recognized as having the greatest potential to replacement for metal fins in thermal management systems such as heat exchangers, space radiators, and thermal protection systems [1–5]. Carbon foam refers to a broad class of materials that include reticulated glassy, carbon and graphitic foams that are generally open-cell or mostly open-cell. They can be tailored to have low or high thermal conductivity with a low coefficient of thermal expansion and density. These foams have high modulus but low compression and tensile strength. Among the carbon foams, the graphitic foam offers superior thermal management properties such as high thermal conductivity. Graphitic foams are made of a network of spheroidal shell segments. Each cell has thin, stretched ligaments in the walls that are joined at the nodes or junctions. The parallel arrangement of graphene planes in the ligaments confers highly anisotropic properties to the walls of the graphitic foams. The graphene planes tend to be oriented with the plane of the ligaments but become disrupted at the junctions (nodes) of the walls. Since conduction is highest along parallel graphene planes, the thermal conductivity is highest in the plane of the ligaments or struts, and much lower in the direction transverse to the plane of these ligaments. In a previous study [6] extensive mechanical and thermal property characterization of carbon foams from Kopper Inc. (L1) and POCO Graphite, Inc. (P1) were reported. These foams were graphitic ones that are expected to have high thermal conductivity. Figure 1 shows sections of light microscopy images of the three foams of four foams. The most important thing to notice is that the images were not at the same magnification. The large cells in the GrafTech foam have an average diameter of only ∼100 μm but have a bimodal distribution cells with many small closed-cells few micrometers in diameter. Changes in density in the GrafTech foam was accompanied by a change in the large cells’ diameter — larger diameter giving greater porosity and lower density without changing the smaller cells’ sizes that filled the solid phase between the larger bubbles. The POCO foam has a fairly uniform size cell distribution of a few hundred micrometers. The Koppers’ foams show larger cells yet with the left (“L” precursor) having a uniform size while the right-hand (“D” precursor) is a less uniform and lower porosity.


1995 ◽  
Vol 10 (2) ◽  
pp. 247-250 ◽  
Author(s):  
Jyh-Ming Ting ◽  
Max L. Lake

The first use of continuous vapor grown carbon fiber (VGCF) as reinforcement in aluminum metal matrix composite (Al MMC) is reported. Al MMC represents a new material for thermal management in high-power, high-density electronic devices. Due to the ultrahigh thermal conductivity of VGCF, 1950 W/m-K at room temperature, VGCF-reinforced Al MMC exhibits excellent thermal conductivity that cannot be achieved by using any other carbon fiber as reinforcement. An unprecedented high thermal conductivity of 642 W/m-K for Al MMC was obtained by using 36.5% of VGCF.


1989 ◽  
Vol 154 ◽  
Author(s):  
John J. Glatz ◽  
Juan F. Leon

AbstractThermal management in the packaging of electronic components is fast becoming an enabling technology in the development of reliable electronics for a range of applications. The objective of the paper is to assess the feasibility of using advance high thermal conductivity pitch fiber (HTCPF) as a solution to some of the packaging problems. The general scope will include the following: identification of the candidate material and its potential applications; thermal management of the chip to board interface; thermal management of the heat within the multi-layer interconnect board (MIB); thermal management of the standard electronic module-format E (SEME); and heat transfer thru the enclosure to a remote heatsink/heat exchanger.


2021 ◽  
Author(s):  
Guanming Yuan ◽  
Zhengwei Cui

Nowadays, polyimide-derived graphite films with high thermal conductivity have been increasingly applied in many cutting-edge fields needing thermal management, such as highly integrated microelectronics and wireless communication technologies. This chapter first introduces a variety of functional graphite films with high thermal conductivity of 500–2000 W/m K in the planar direction, then provides the preparation technology (including lab-scale preparation and industrial production) and quality control strategy of high-thermal-conductivity graphite films, which are derived from a special polymer- polyimide (PI) by carbonization and graphitization treatments through a suitable molding press in a vacuum furnace. The morphology, microstructure and physical properties as well as the microstructural evolution and transformation mechanism of PI films during the whole process of high-temperature treatment are comprehensively introduced. The nature of PI precursor (e.g., the molecular structure and planar molecular orientation) and preparation technics (e.g., heat-treatment temperature and molding pressure) are critical factors influencing their final physical properties. Currently challenged by the emerging of graphene-based graphite films, the latest developments and future prospects of various PI-derived carbons and composites (beyond films) with high thermal conductivity have been summarized at the end. This chapter may shed light on a promising and versatile utilization of PI-derived functional carbon materials for advanced thermal management.


Sign in / Sign up

Export Citation Format

Share Document