Engineers at the University of Michigan, Ann Arbor, have developed a plastic blend that, they say, can dissipate heat up to 10 times better than its conventional counterparts. While plastics are inexpensive, lightweight, and flexible, they tend to restrict the flow of heat, so their use has been limited in technologies like computers, smartphones, and other devices. This new research could lead to light, versatile, metal-replacement materials for more powerful electronics.
Previous efforts to boost heat transfer in polymers have relied on metal or ceramic filler materials or stretching molecule chains into straight lines. Those approaches can be difficult to scale up and can increase a material's weight and cost, make it more opaque, and affect how it conducts electricity and reflects light. The researchers say that their blended material has none of those drawbacks, and is easy to manufacture using conventional methods.
The researchers devised a way to strongly link long polymer chains of a plastic called polyacrylic acid with short strands of another called polyacryloyl piperidine. 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.
They say that improving those connections allows the heat energy to find continuous pathways through the material. Some samples conducted heat exceptionally well, they said. By performing numerous measurements of the polymer blend structures and their physical properties, the engineers learned many important material design principles governing heat transfer in amorphous polymers.
