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Researchers at the University of Michigan have made a plastic that is ten times better at dispersing heat than conventional plastics and could be used to replace metals.
According to the researchers, the plastic could lead to lighter, versatile, metal-replacement materials that will be used in more powerful electronics or more efficient vehicles.
Kevin Pipe, associate professor of mechanical engineering at the University of Michigan, said: "Researchers have paid a lot of attention to designing polymers that conduct electricity well for organic LEDs and solar cells, but engineering of thermal properties by molecular design has been largely neglected, even though there are many current and future polymer applications for which heat transfer is important.”
The material is unlike previous efforts to boost heat transfer in polymers because it does not use a metal or ceramic filler. The use of a filler has several drawbacks: it can be difficult to scale up, increase a materials weight and cost, make it more opaque and affect how it conducts electricity and reflects light.
The research, which is one of the first attempts to engineer the flow of heat in an amorphous polymer, linked long polymer chains of a plastic called polyacrylic acid (PAA) with short strands of another called polyacryloyl piperidine (PAP). The blend relies on hydrogen bonds that are 10-to-100 times stronger than the forces that loosely hold together the long strands in most other plastics. The PAP plastic strands were blended separately with three other polymers that they knew would form hydrogen bonds in different ways. The researchers then tested how each conducted heat.
Jinsang Kim, associate professor of materials science and engineering, at the University of Michigan said: "We improved those connections so the heat energy can find continuous pathways through the material.
"There's still a long way to go, but this is a very important step in understanding how to engineer plastics in this way. Ten times better is still a lot lower heat conductivity than metals, but we've opened the door to continue improving.”
The study has been published in the journal Nature Materials and was was funded by the U.S. Department of Energy.