Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researcher reports nano-particle dispersion technique improves polymers

30.08.2005


Supercritical fluid carbon dioxide used; melt properties provide monitor



There is a lot of excitement about incorporating nano particles into polymers because of the ability to improve various properties with only a small percent of the particles. "You can improve the barrier to gases, such as hydrogen, carbon dioxide, and oxygen. You can increase material strength with little increase in weight," said Don Baird, professor of chemical engineering at Virginia Tech.

But there are problems. "While 1 percent by weight of nano particles will change a material’s properties dramatically, 2 or 3 percent provides hardly any additional enhancement," he said. "The particles just clump together, and thereby reduce the advantages associated with the surface area of single particles."


Another problem is that the incorporation of nano particles changes a polymer’s flow properties leading to potential processing problems.

Baird’s research group at Virginia Tech has developed a method for improving the dispersion, or exfoliation, of individual nano particles into polymers. He will present his research at the 230th American Chemical Society National Meeting, held in Washington, D.C., Aug. 28-Sept. 1. "The paper will present how we are dispersing nano particles and how we are using flow properties to monitor dispersion," he said.

Using supercritical carbon dioxide, the researchers are able to exfoliate nano particles at higher concentrations, leading to further enhancement of mechanical properties than presently possible using just mechanical mixing. "Carbon dioxide is soluble in a lot of polymers. It attaches to the particles so they don’t attach to each other, and helps disperse the particles throughout the polymer. It is a benign, natural substance," Baird said.

The rheological properties including the normal stresses (elastic properties) and the stress relaxation response are used to monitor particle dispersion.

The researchers also have discovered that the changed flow behavior is good news – an indication that the material will exhibit improved mechanical properties.

Baird’s team observed that nano clay particles well dispersed in polypropylene and polycarbonate plastics tend to promote polymer chain orientation, or alignment, and then retard relaxation or loss of orientation. "The result is they make the polymer chains act like longer or higher molecular weight chains. The material is stronger than one would expect given the size of a polymer chain."

Pointing to a bobbin of fiber, Baird said, "If that contained nano particles and was stretched, it is possible that the fiber could be woven into a vest that would stop a bullet. An ordinary polymer material with well dispersed high levels (8 wt%) of nano particles could have exceptional mechanical properties."

He will present the paper, "Effects of nano clay particles on non-linear rheology of polymer melts (Poly 248)" at 11:20 a.m. Monday, Aug. 29, in the Grand Hyatt Constitution room D-E, as part of the Herman Mark Award program honoring Don Paul.

Susan Trulove | EurekAlert!
Further information:
http://www.che.vt.edu/baird/baird.htm
http://www.vt.edu

More articles from Materials Sciences:

nachricht Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>