PEI honeycomb cores: Sustainable and top-performing

Key points:

• Aerospace parts with thermoplastic PEI honeycombs can be weight and cost competitive to conventional thermoset sandwich panels and parts.
• ThermHex PEI honeycombs allow an improvement of fire safety and FST performance compared to conventional panels.
• Wavy cell wall geometry offers remarkable increase of mechanical performance of PEI honeycombs compared to honeycombs with a hexagonal geometry.
• This thermoplastic honeycomb core is thermoforbale and can be processed into 3D sandwich parts using conventional compression moulding
• Continuously produced PEI thermoplastic honeycomb is a major step towards reduction of

  CO₂-footprint and opens up the path to recyclable aircraft interior panels and parts.

Polyetherimide (PEI) honeycomb cores are thermoplastic cores developed to provide a more sustainable material solution, particularly for aerospace applications or railway interior components, where non-recyclable thermoset phenolic resin honeycombs have been used for a long time. ThermHex PEI honeycomb cores now enable modern industry to use recyclable production materials without compromising on market requirements regarding fire safety, weight and performance. This is because their optimally structured inner geometry drastically increases buckling resistance under out-of-plane compression and shear loads.

Key applications of PEI honeycomb cores: aircraft and railway interior

Whilst ThermHex PEI honeycomb cores are produced efficiently using the proven EconCore technology, they offer great potential in terms of increasing production efficiency. This product has been developed with a focus on health, fire safety and the environment.
PEI honeycomb cores are typically laminated with fibre-reinforced thermoplastic composites to create a monomaterial, all-thermoplastic and thermoformable sandwich solution. In other cases, this honeycomb core can be laminated with thermoset (e.g. epoxy) prepeg skins allowing for construction of phenolic-free panels.

New patent brings key advantages in buckling resistance

Last but not least, a key innovation of this technology is EconCore’s new patented ThermHex wavy cell wall, which allows the PEI honeycomb to be brought to the conservative aerospace market. This is because the continuously produced PEI honeycomb has optimally structured wavy cell walls that drastically increase its resistance to buckling under out-of-plane compression and shear loads, which are the key mechanical properties of honeycomb cores.

Product Properties

The physical properties of ThermHex honeycomb cores are mainly defined by the following characteristics:

Core thickness and cell size

ThermHex PEI honeycomb cores are produced in different core thicknesses and cell sizes. Please refer to data sheets or ask us for avaiable configurations.

Density

ThermHex PEI honeycomb cores are produced with densities of 48 – 96 kg/m³. 32 kg/m³ as well as densities above 96 kg/m³ are a technological option, too.