Meet the Need for New and Innovative Cooling Techniques with Thermally Conductive Plastics (TCP) Containing Boron Nitride

According to the US Air Force, 55% of their electronic component failures are due to temperature.*

With increasing global trends in miniaturization of electronic systems and weight savings in transportation, designers and material engineers need to find innovative solutions to meet the thermal management requirements of more compact designs

Boron nitride: An excellent heat conductor and electrical insulator

Boron nitride (BN) has been gaining interest as a filler in thermoplastics to increase thermal conductivity of resins. It is unique in the sense that it is an excellent conductor of heat yet still electrically insulating.

Plastics containing BN are being used to replace traditional metal parts in a number of markets to improve heat-related performance and increase the lifetime of systems. Overall system cost and complexity can be reduced.

Examples of potential applications include under-the-hood automotive parts, sensors and housings for motors, LEDs and many other electronic devices, molded heat sinks, and medical device components - basically, anywhere heat is an issue.

For more details contact : innovative_growth@yahoo.co.in

A New Progress Made For The Research of Metallic Boron Nitride

Recently a new progress on metallic Boron Nitride (BN) has been made by Prof. Qian Wang’s group at the Center for Applied Physics and Technology (CAPT), College of Engineering at Peking University and her collaborators. With the aid of state-of-the-art theoretical calculations, they proposed new BN allotropes which exhibit unusual metallicity. This work is recently published in Journal of the American Chemical Society (J. Am. Chem. Soc.2013, 135, 18216？18221).

How to convert an insulator or semiconductor into a metal is an important and fundamental topic. Much of the current electronics depend upon this. For nearly a century this is primarily accomplished by doping. Manipulating their structure to induce a metallic transition, however, has not been a common practice. It is in this aspect that Wang and co-workers focused on BN which is a chemical analogue of Carbon and shares with it similar structures such as one-dimensional nanotube, two-dimensional nanosheet characterized by sp² bonding, and three-dimensional (3D) diamond structure characterized by sp³ bonding. However, unlike Carbon which can be metallic in certain forms, BN is an insulator, irrespective of its structure and dimensionality. Taking the advantage of boron’s capacity to form multielectron-multicenter bonds, Wang and co-workers designed the tetragonal structures of BN containing both sp² and sp³ hybridizations based on first-principle density-functional calculations. The new phases of BN are both dynamically stable and metallic. Analysis of their electronic structures reveals the metallic behavior comes from the delocalized B 2p electrons. The metallicity exhibited in the studied 3D BN structures can lead to materials beyond conventional ceramics as well as to materials with novel transport properties and potential for applications in electronic devices. High-temperature insulator has metallic potential. This work may stimulate experimentalists to synthesize these novel forms of metallic BN and once that is achieved, it will have transformative impact on science and technology.

This work has been highlighted by “Spotlights on Recent JACS Publications” and Chemistryviews:

http://pubs.acs.org/doi/pdfplus/10.1021/ja4124016

Thermally Conductive, Electrically Insulating and melt-processable Polystyrene/Boron nitride Nanocomposites Prepared by in situ Reversible Addition Fragmentation Chain Transfer Polymerization

ABSTRACT 

Thermally conductive and electrically insulating polymer/boron nitride (BN) nanocomposites are highly attractive for various applications in many thermal management fields. However, so far most of the preparation methods for polymer/BN nanocomposites have usually caused difficulties in the material post processing. Here, an in situ grafting approach is designed to fabricate thermally conductive, electrically insulating and post-melt processable polystyrene (PS)/BN nanosphere (BNNS) nanocomposites by initiating styrene (St) on the surface functionalized BNNSs via reversible addition fragmentation chain transfer polymerization. The nanocomposites exhibit significantly enhanced thermal conductivity. For example, at a St/BN feeding ratio of 5:1, an enhancement ratio of 1375% is achieved in comparison with pure PS. Moreover, the dielectric properties of the nanocomposites show a desirable weak dependence on frequency, and the dielectric loss tangent of the nanocomposites remains at a very low level. More importantly, the nanocomposites can be subjected to multiple melt processing to form different shapes. Our method can become a universal approach to prepare thermally conductive, electrically insulating and melt-processable polymer nanocomposites with diverse monomers and nano fillers.


The authors of this publication are on ResearchGate and have made the full-text available on their profiles. Department of Physics, Michigan Technological University, 118 Fisher Hall, 1400 Townsend Drive, Houghton, MI 49931, USA. 
Nanoscale (Impact Factor: 6.73). 10/2010; 2(10):2028-34. DOI: 10.1039/c0nr00335b 

Source: PubMed