Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carnegie Mellon scientists use 'green' approach to transform plastics manufacturing

10.10.2006
Landmark results will reduce costs for industry, expand products

Using environmentally safe compounds like sugars and vitamin C, scientists at Carnegie Mellon University have vastly improved a popular technology used to generate a diverse range of industrial plastics for applications ranging from targeted drug delivery systems to resilient paint coatings.

The revolutionary improvement in atom transfer radical polymerization (ATRP) now enables large-scale production of many specialty plastics, according to the scientists, whose work appears in a special issue of the Proceedings of the National Academy of Sciences (PNAS) devoted to materials science. This edition will be published Oct. 17.

The new "green" version of ATRP will allow existing materials to be made more efficiently, reducing industrial purification costs before and after running a reaction and permitting the production of new, unprecedented materials.

"By reducing the level of the copper catalyst used in ATRP, we have made this process at least 100 times more efficient and much more amenable to industrial processes," said Krzysztof Matyjaszewski, J.C. Warner Professor of Natural Sciences and director of the Center for Macromolecular Engineering in the Mellon College of Science at Carnegie Mellon.

Developed by Matyjaszewski, ATRP is a broadly adopted process that allows the production of specialty polymers for coatings, adhesives, lubricants, cosmetics, electronics and numerous other markets. ATRP's strength lies in its ability to combine chemically diverse subunits (monomers) into multiple arrangements that create specialized polymers. This technology enables production of "smart" materials that can respond intelligently to altered environments, such as changes in pressure, acidity, light exposure and other variables.

ATRP is being licensed to several companies that have already begun commercial production in the United States, Europe and Japan. But Matyjaszewski says large-scale production of polymers by ATRP has been limited because ATRP previously required a high concentration of copper catalyst that had to be removed from finished products.

"Our new ATRP processes significantly reduce the cost of recycling the catalyst and also decrease the release of hazardous reaction byproducts found in industrial waste," Matyjaszewski added.

During ATRP, scientists produce a complex polymer structure using a special catalyst to add one or a few monomer units at a time to a growing polymer chain. ATRP requires a balance between two species of copper (Cu) catalyst, CuI and CuII. But as an ATRP reaction progresses, CuII builds up. Typically, researchers add more CuI to compensate for this effect and maintain the balance between the two copper species. But this approach ultimately generates materials with high overall levels of copper -- levels that are too costly to remove efficiently on a large-scale industrial basis.

The PNAS report highlights the team's novel use of "excess reducing agents" to lower the amount of copper catalyst from 5,000 parts per million (ppm) to 10 ppm. The team showed that you can steadily add environmentally benign "reducing" agents -- vitamin C, sugars or standard free radicals -- to chemically reduce CuII to CuI. This unprecedented approach continuously reduces CuII to CuI at the same rate CuII forms while retaining the desired balance between the two states. Ultimately, this technique dramatically lowers the overall amount of Cu catalyst used in ATRP by as much as 1,000 times.

The team's new technology virtually eliminates the need to remove miniscule amounts of catalyst remaining in a product. For example, many ATRP-generated plastics for medical implants would be acceptable from a health perspective because they contain so little copper. However, if the target application -- such as a coating for a biomedical stent -- absolutely requires the removal of residual catalyst, companies will now have much less of it to take out, significantly lowering removal costs, according to the authors.

The new ATRP technique also allows for production of higher molecular weight chains, thereby extending the range of accessible materials that could be made using this method. For example, chemists could grow high molecular weight polymers with precise control, providing even larger templates for nanoscale carbon structures used in computer screen field emission displays and semi-conductors that regulate the flow of electricity in sensors, some only a fraction of the width of a hair.

ATRP differs significantly from conventional polymer manufacturing methods. This "living," synthetic process can be shut down or restarted at will, depending on how the temperature and other conditions of the reaction are varied. ATRP is an exceptionally robust way to uniformly and precisely control the chemical composition and architecture of polymers as well as the growth of every polymer chain, all while employing a broad range of monomers.

Much of the research progress and commercial success related to ATRP is due to two research consortia Matyjaszewski has initiated and led. These successful consortia have allowed many companies to incorporate ATRP methodologies into the development of new products for their specific markets. Companies from around the world send their employees to train in Matyjaszewski's laboratory.

Lauren Ward | EurekAlert!
Further information:
http://www.chem.cmu.edu/groups/maty/center/

More articles from Materials Sciences:

nachricht How effective are bonding agents? Fraunhofer uses liquid chromatography for characterization
24.10.2017 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Flying: Efficiency thanks to Lightweight Air Nozzles
23.10.2017 | Technische Universität Chemnitz

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Single nanoparticle mapping paves the way for better nanotechnology

24.10.2017 | Physics and Astronomy

A quantum spin liquid

24.10.2017 | Physics and Astronomy

Antibiotic resistance: a strain of multidrug-resistant Escherichia coli is on the rise

24.10.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>