Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Epoxy compound gets a graphene bump

14.11.2018

Rice scientists combine graphene foam, epoxy into tough, conductive composite

Rice University scientists have built a better epoxy for electronic applications.


Led by scientists at Rice University, researchers have created an epoxy-graphene foam compound that is tough and conductive without adding significant weight. The material is suitable for applications like electromagnetic shielding.

Credit: Rouzbeh Shahsavari Group/Rice University

Epoxy combined with "ultrastiff" graphene foam invented in the Rice lab of chemist James Tour is substantially tougher than pure epoxy and far more conductive than other epoxy composites while retaining the material's low density. It could improve upon epoxies in current use that weaken the material's structure with the addition of conductive fillers.

The new material is detailed in the American Chemical Society journal ACS Nano.

By itself, epoxy is an insulator, and is commonly used in coatings, adhesives, electronics, industrial tooling and structural composites. Metal or carbon fillers are often added for applications where conductivity is desired, like electromagnetic shielding.

But there's a trade-off: More filler brings better conductivity at the cost of weight and compressive strength, and the composite becomes harder to process.

The Rice solution replaces metal or carbon powders with a three-dimensional foam made of nanoscale sheets of graphene, the atom-thick form of carbon.

The Tour lab, in collaboration with Rice materials scientists Pulickel Ajayan, Rouzbeh Shahsavari and Jun Lou and Yan Zhao of Beihang University in Beijing, took their inspiration from projects to inject epoxy into 3D scaffolds including graphene aerogels, foams and skeletons from various processes.

The new scheme makes much stronger scaffolds from polyacrylonitrile (PAN), a powdered polymer resin they use as a source of carbon, mixed with nickel powder.

In the four-step process, they cold-press the materials to make them dense, heat them in a furnace to turn the PAN into graphene, chemically treat the resulting material to remove the nickel and use a vacuum to pull the epoxy into the now-porous material.

"The graphene foam is a single piece of few-layer graphene," Tour said. "Therefore, in reality, the entire foam is one large molecule. When the epoxy infiltrates the foam and then hardens, any bending in the epoxy in one place will stress the monolith at many other locations due to the embedded graphene scaffolding. This ultimately stiffens the entire structure."

The puck-shaped composites with 32 percent foam were marginally denser, but had an electrical conductivity of about 14 Siemens (a measure of conductivity, or inverse ohms) per centimeter, according to the researchers. The foam did not add significant weight to the compound, but gave it seven times the compressive strength of pure epoxy.

Easy interlocking between the graphene and epoxy helped stabilize the structure of the graphene as well. "When the epoxy infiltrates the graphene foam and then hardens, the epoxy is captured in micron-sized domains of the graphene foam," Tour said.

The lab upped the ante by mixing multiwalled carbon nanotubes into the graphene foam. The nanotubes acted as reinforcement bars that bonded with the graphene and made the composite 1,732 percent stiffer than pure epoxy and nearly three times as conductive, at about 41 Siemens per centimeter, far greater than nearly all of the scaffold-based epoxy composites reported to date, according to the researchers.

Tour expects the process will scale for industry. "One just needs a furnace large enough to produce the ultimate part," he said. "But that is done all the time to make large metal parts by cold-pressing and then heating them."

He said the material could initially replace the carbon-composite resins used to pre-impregnate and reinforce fabric used in materials from aerospace structures to tennis rackets.

###

Visiting Rice student Xiao Han, a graduate student at Beihang University, and Rice graduate student Tuo Wang are co-lead authors of the paper. Co-authors are Rice alumni Peter Samora Owuor and Jongwon Yoon, graduate student Sung Hoon Hwang, visiting scholars Chao Wang and Lulu Shen, and postdoctoral researchers Weipeng Wang and Rodrigo Villegas Salvatierra; and Junwei Sha of Tianjin University, China.

Ajayan is chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry. Shahsavari is an assistant professor of civil and environmental engineering and of materials science and nanoengineering. Lou is a professor of materials science and nanoengineering. Zhao is a professor at Beihang University. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research and the China Scholarship Council supported the research.

Read the abstract at https://pubs.acs.org/doi/10.1021/acsnano.8b05822.

This news release can be found online at http://news.rice.edu/2018/11/14/epoxy-compound-gets-a-graphene-bump/

Follow Rice News and Media Relations via Twitter @RiceUNews.

Related materials:

Rice U. chemists create 3D printed graphene foam: http://news.rice.edu/2017/06/21/rice-u-chemists-create-3-d-printed-graphene-foam/

James M. Tour Group: https://www.jmtour.com

Ajayan Research Group: http://ajayan.rice.edu

Multiscale Materials Laboratory: https://rouzbeh.rice.edu

Lou Group: http://n3lab.rice.edu

Rice Department of Chemistry: https://chemistry.rice.edu

Rice Department of Materials Science and NanoEngineering: https://msne.rice.edu

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 2 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview.

Media Contact

David Ruth
david@rice.edu
713-348-6327

 @RiceUNews

http://news.rice.edu 

David Ruth | EurekAlert!
Further information:
http://dx.doi.org/10.1021/acsnano.8b05822

Further reports about: Materials Science NanoEngineering epoxy foam graphene graphene foam

More articles from Materials Sciences:

nachricht Pressure tuned magnetism paves the way for novel electronic devices
18.12.2018 | Bar-Ilan University

nachricht Researchers observe charge-stripe crystal phase in an insulating cuprate
18.12.2018 | Boston College

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Pressure tuned magnetism paves the way for novel electronic devices

18.12.2018 | Materials Sciences

New type of low-energy nanolaser that shines in all directions

18.12.2018 | Physics and Astronomy

NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate

18.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>