Smart blending plastics

A new ‘smart blending’ process developed by Clemson University researchers could change the way plastics are made as well as improve their performance.

Early results published in August’s ‘Polymer Engineering and Science’ have already drawn interest from European and US plastics manufacturers.

Dave Zumbrunnen, who heads the Clemson research team, said smart blending could bring plastics production into the 21st century.

‘Most people would be surprised to learn that many plastics are not optimised for their intended use due to limitations of existing manufacturing equipment,’ he said. With a smart-blending machine, however, engineers can optimise the material for maximum effectiveness with only a few strokes on a computer keyboard.

Many plastics are mixtures of two or more plastics and additives. Smart blending techniques cause initially large and segregated molten thermoplastic streams and additives to refine and undergo a sequence of controllable morphological changes leading to novel blends with a variety of shapes at the micro- and nano-scale.

That’s important because it’s those small-scale structures that determine the attributes, or properties, of the plastic or composite.

The end result? Plastics that are tougher, electrically conductive, porous – whatever is needed for the particular end-product, but without expensive trial and error.

‘Smart blending technology offers unprecedented control of internal structure development, said Zumbrunnen. He developed the process along with faculty and student researchers from Clemson’s Center for Advanced Engineering Fibers and Films.

Immediate applications could include improved food packaging films, personal hygiene products, light-interactive plastics and toughened plastics for automotive uses. Smart blending could also be used to produce patterns for countertops and even better tasting breakfast cereals.

The Dow Chemical Company is funding a smart blending study through the fibres and films centre. ‘We are looking forward to the results and the further development of this technology,’ said Craig Dryzga, senior R&D leader in Dow’s Fabricated Products Department.

Zumbrunnen’s research sponsors include industry representatives such as Dow, as well as the National Science Foundation, Defense Advanced Research Projects Agency and the National Textile Center.

Equipment manufacturers are interested in commercialising the technology. Zumbrunnen predicted that the first wave of smart-blended plastics could be on the market within a few years.

Zumbrunnen’s research is based on the work of Hassan Aref, who developed what’s known as the theory of chaotic advection. In a seminal 1980s paper, Aref showed that particles in a fluid can move chaotically in response to simple agitations. The chaotic motions cause fluidic regions to become stretched and folded, forming the layers on which Zumbrunnen has based his work.

A tutorial on the subject is available on the web <a href=’http://www.ces.clemson.edu/mmpl/concepts/tutorial.html’>here</a>.

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