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Plastics that are usually thermally insulating
are never considered as potential materials for any application that
requires removing heat. Several compounders/producers have been recently
developing heat-conducting thermoplastic compounds that will have
thermal conductivity as high as 60W/mk. Initial developments have
been concentrated on heat-resistant engineering polymers such as LCP,
PPS, PEEK and Polysulphones. Newer developments are based on medium
temperature resistant polymers such as ABS, PBT, Polycarbonate and
Nylon. There seems to be an opportunity for PP and PS in non-electronic
applications such as food packaging heating and cooling products.
To achieve thermal conductivity additives like graphite,
carbon fibers, and ceramics like Aluminum Nitride or Boron Nitrides
are used. Graphite provides electrical as well as thermal conductivity
while ceramics provide only thermal conductivity. Graphite fibers
made from petroleum pitch are excellent thermal conductors while
the structural graphites have lower thermal conductivity. High loadings
as high as 70% of fibers are required to achieve good thermal conductivity.
These thermally conductive plastic compounds are quite expensive
mainly due to higher cost of fibers.
The major applications for thermally conductive plastics
would be in microelectronics to provide the desired heat sinks to
pack more in smaller space. The common uses are circuit boards,
tubing for heat exchanger in appliances. Newer applications will
emerge once their costs are lowered.
The major players in thermally conductive products
are: A. Schulman, Cool Polymers, Dupont, GE Plastics, LNP, PolyOne,
RTP and Ticona.
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