The spaghetti-like internal structure of most plastics makes it hard for them to cast away heat, but a University of Michigan research team has made a plastic blend that does so 10 times better than its conventional counterparts.
Plastics are inexpensive, lightweight and flexible, but because they restrict the flow of heat, their use is limited in technologies like computers, smartphones, cars or airplanes—places that could benefit from their properties but where heat dissipation is important. The new U-M work could lead to light, versatile, metal-replacement materials that make possible more powerful electronics or more efficient vehicles, among other applications.
The new material, which is actually a blend, results from one of the first attempts to engineer the flow of heat in an amorphous polymer. A polymer is a large molecule made of smaller repeating molecules. Plastics are common synthetic polymers.
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 U-M material has none of those drawbacks, and it’s easy to manufacture with conventional methods, the researchers say.
“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,” said Kevin Pipe, U-M associate professor of mechanical engineering and corresponding author of a paper on the work published in the current issue of Nature Materials.
Pipe led the project with Jinsang Kim, another corresponding author and associate professor of materials science and engineering.
Heat energy travels through substances as molecular vibrations. For heat to efficiently move through a material, it needs continuous pathways of strongly bound atoms and molecules. Otherwise, it gets trapped, meaning the substance stays hot.
“The polymer chains in most plastics are like spaghetti,” Pipe said. “They’re long and don’t bind well to each other. When heat is applied to one end of the material, it causes the molecules there to vibrate, but these vibrations, which carry the heat, can’t move between the chains well because the chains are so loosely bound together.”
The Pipe and Kim research groups devised a way to strongly link long polymer chains of a plastic called polyacrylic acid (PAA) with short strands of another called polyacryloyl piperidine (PAP). The new 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.
“We improved those connections so the heat energy can find continuous pathways through the material,” Kim said. “There’s still a long way to go, but this is a very important step we made to understand 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 Latest on: Heat-conducting plastic
via Google News
The Latest on: Heat-conducting plastic
- Bizarre Things: Matter & Energyon March 20, 2020 at 5:00 pm
Mar. 18, 2020 — A new type of robot combines traditional and soft robotics, making it safe but sturdy. Once inflated, it can change shape and move without being attached to a source of energy or ...
- Building A DIY Heat Pipeon March 19, 2020 at 5:00 pm
Once the secret design tool for aerospace designers, the heat pipe is a common fixture now thanks to the demands of PC CPU cooling. Heat pipes can transfer lots of energy from a hot side to a cold ...
- Fail Of The Week: Taking Apart A Tesla Batteryon March 17, 2020 at 5:00 pm
That means that to remove the individual cells without damaging them, several layers of glue and plastic have to be removed before you can start hammering the cells out with a PEX wedge and a hammer.
- Hermle Builds Hybrid 5-axis CNC Mill & 3D Printing Marvel – The MPA 40on March 15, 2020 at 5:00 pm
This time we talk about scale in 3D printing ... cooling channels in plastic injection molds. This micro-forging means dissimilar materials like a heat-conducting copper core inside a tool ...
- Graphite foil keeps small planes flyingon March 5, 2020 at 4:00 pm
The heaters, actually a three-ply tape, are comprised of an outer heat-conducting plastic, a layer of expanded graphite foil that heats up when energized, and an electrically insulating base layer.
- Heraeus SCB technology enhances thermal management in LED luminaireson February 20, 2020 at 4:00 pm
As a result the inexpensive SCB mass production process means that modular superstructures can be achieved which are capable of producing overall heat conducting values comparable to those of ceramic ...
- Heat Conductive Plastic Materialson February 20, 2018 at 6:53 am
Description: Master Bond Polymer System EP21TCHT-1 is a two component, thermally conductive, heat resistant, epoxy compound formulated to cure at ambient temperatures or more rapidly at elevated ...
- Fiberglass Reinforcedon February 16, 2018 at 12:39 pm
Description: Redco™ Fiberglass Reinforced Plastic Grating Redco FRP Grating provides durability with extremely high strength and stiffness. Due to its high load capacity it can be used with confidence ...
via Bing News