Plastic typically cannot withstand heat. This new type is different: it can withstand the intense heat of extreme combustion without melting and turning into a viscous mass.
A team of researchers from South Korea has designed a polymer composite that maintains its structure even in flames approaching 1,000 °C, paving the way for lighter aircraft enginessafer electric vehicle batteries and other technologies where heat plays an important role.
The results of the research, led by Oh Young-seok, a researcher at the Korea Institute of Materials Science, were presented in a published this month in the journal Advanced Composites and Hybrid Materials.
At the heart of this advancement is a architectural trick unusual. Instead of altering the chemistry of the plastics, the team of researchers built a three-dimensional structure of carbon nanotubes which physically traps the polymer chains, limiting freedom of movement when heated.
Most modern planes and vehicles use polymer composites because they are light and easy to shape. But heat continues to be a problem.
Above a certain temperature, the molecular movement increases and the material loses rigidity, forcing engineers to resort to heavier metalslike titanium, explains the .
Previous attempts have sought to chemically reinforce polymers or blend nanoparticles. These strategies helped, but only slightly. The new study focuses instead on the nanoconfinamento — restrict the movement of polymers by surrounding the chains with a rigid structure.
The researchers fabricated a three-dimensional porous nanotube network single-walled carbon with pores of just a few nanometers wide. After infused epoxy resin in this “nano cage”creating interconnected networks of nanotubes and polymer.
Like the tiny pores are smaller than space that the polymer chains need to move, heat has much less ability to soften the material in the usual way. Tests demonstrated that the chains remain largely trapped inside the cage.
This means that the plastic maintains rigidity at temperatures in which common epoxy deforms, presents much less creep under tension and expands very little when heated. Its thermal expansion has decreased by more than 98% compared to the original polymer.
To make the material more practical for real-world useresearchers combined the nanotube cage with carbon fiber fabric, creating a layered composite that combines nanometer-scale strength with the durability of traditional reinforcement.
This hybrid material maintained more than 90% of its rigidity up to approximately 370 °C — remaining rigid at temperatures where many aerospace titanium alloys begin to lose strength.
In flame tests that reached ca. 1.000 °Cstructures containing the nanocage resisted visible combustion for much longer than conventional carbon fiber composites.
Simply put, this means that the plastic could be used in applications that involve a lot of heat, such as lighter engine componentsstructures of heat-resistant supersonic vehicles and battery casings that slow the spread of fires. Even incremental changes to materials can have large environmental and economic effects in aviation and transport.
