Heat-conducting plastic may lead to lighter cars, computers

Scientists have developed a new heat-conducting plastic that may lead to lighter and more energy-efficient vehicles and computer devices.
Researchers used a new technique to change the plastic's molecular structure to help it cast off heat, making it six times better at dissipating heat.
"Plastics are replacing metals and ceramics in many places, but they're such poor heat conductors that nobody even considers them for applications that require heat to be dissipated efficiently," said Jinsang Kim, professor at the University of Michigan in the US.
"We're working to change that by applying thermal engineering to plastics in a way that hasn't been done before," said Kim.

The process is a major departure from previous approaches, which have focused on adding metallic or ceramic fillers to plastics.
This has met with limited success; a large amount of fillers must be added, which is expensive and can change the properties of the plastic in undesirable ways.

Instead, the new technique uses a process that engineers the structure of the material itself.
Plastics are made of long chains of molecules that are tightly coiled and tangled. As heat travels through the material, it must travel along and between these chains - a journey that impedes its progress.
The team including graduate student Apoorv Shanker used a chemical process to expand and straighten the molecule chains.

This gave heat energy a more direct route through the material.
Pipe said that the work can have important consequences because of the large number of polymer applications in which temperature is important.