Patented composite is hot stuff

Researchers at Ohio State University have patented a tough, heat resistant plastic that may soon find its way into aircraft and motor vehicle engines.

The Ohio State researchers discovered the new composite after mixing plastic with silica to create a material said to be three to four times tougher than the plastic.

The new composite material is tougher than plastic due to its ability to divide the force of an impact into many small interactions involving millions of individual silica particles.

‘We think that as a crack starts travelling through the composite, it breaks up into finer and finer cracks, until the material has dissipated the energy of the impact,’ said John Lannutti, associate professor of materials science and engineering at Ohio State University.

Lannutti and his colleagues call the method ‘synergistic toughening,’ or ‘toughening across scales’, because it strengthens material down to the scale of the individual particles.

The silica particles used by Lannutti and his team are only 50 nanometers wide and each particle contains a host of even smaller pores that measure a few nanometers across.

What makes the patented manufacturing method unique is that the researchers force melted plastic to fill these tiny pores, creating a strong bond between atoms of silica and plastic over a large surface area.

It was military testing of parts made with heat-resistant plastic and reinforced with graphite fibre that uncovered the need for tougher plastics.

Impacts, such as a bird flying into an aircraft wing, would shatter the plastic and leave behind only the woven graphite fibres, Lannutti said.

The brittle plastic’s tolerance of temperatures up to 800°F gives the material the potential to be used for parts surrounding jet engines.

In laboratory tests, the plastic-silica composite material retained the heat-resistance of fibre-reinforced plastics, but improved resistance to impacts by four to five times.