Tougher Heat-Resistant Plastics

Description and Advantages

Mixing heat-resistant plastic with silica, US scientists have developed a new material that is four times tougher than the plastic. Plastic engine parts would mean lighter, more fuel-efficient cars and airplanes, but today’s heat-resistant plastics are not tough enough - they shatter at the smallest impact. The new composite material is tougher than plastic as it divides the force of an impact into many small interactions involving millions of individual silica particles, says researchers from Ohio State University in Columbus, who have developed it.

Using a method, which they term as "synergistic toughening" or toughening across scales as it strengthens material down the scale of the individual particles, the researchers force melted plastic to fill tiny pores in silica particles, creating strong bonds between silica atoms and plastic over a large surface area, according to university release. The silica particles used are 50 nanometers wide - about 100 times smaller than the width of a human hair - and each particle contains a host of even smaller pores that measure only a couple of nanometers across. Toughness, therefore, starts at nanoscale, says Lannutti.

The brittle plastic’s tolerance of temperatures upto 800oF makes it ideal for parts surrounding hot jet engines. In laboratory tests, the plastic-silica composite material retained the heat-resistance of fiber-reinforced plastics, but improved resistance to impacts by four to five times. The composite is not as hard as steel, but displays good heat resistance at a fraction of the weight of steel, the release says.

Application

This new plastic can be used in car and aircraft engines, which are currently made using iron, steel and aluminium.

Source: PTI Science Service, October 1-15, 2000