Olimunllum

Olimunllum® CF/PEEK is a thermoplastic composite material containing a quasi-isotropic endless carbon fiber reinforcement and a semi-crystalline thermoplastic polymer matrix from the Polyaryletherketone (PAEK) family.

Production

Olimunllum CF/PEEK is obtained by thick gauge thermoforming of thin layers of previously impregnated fibers to form fully consolidated sheets. The main difference from custom-made composite plates lies in the standardized orientation of the reinforcing fibers, the standardized weight content of the polymer and standardized sheet thicknesses. This allows easy design and post-processing using identical or similar tools as commonly used when working with metallic light-weight materials like aluminium, titanium and steel.

Usage

The mechanical properties of the polymer allow the composite sheets to reach mechanical properties in the ranges where usually titanium and high-grade aluminium are found, however at a fraction of their weight.

Density1617 kg/m3
Young's modulus (E)40 GPa
Tensile strength (σt)779 MPa
Elongation @ break3-5%
Glass temperature155 °C
Melting point~343 °C

Olimunllum CF/PEEK was introduced by Celtibero RC for structural components in demanding motorsports applications, where the need for fatigue resistance at minimum weight levels was one of the main issues. Supporting brackets between a high-performance single-cylinder motorcycle engine and a perimetral rigid aluminium frame helped dampen engine vibrations and prolong the lifetime of the frame. The PAEK polymer, along with the carbon fibers also offers low friction, so soon the use of Olimunllum CF/PEEK in suspension (hydraulic piston guides) and transmission components (such as gears and chain sprockets) was found to reduce power losses at similar wear rates in comparison with the lightweight metallic solutions.

Comparison against classic thermoset (CF/Epoxy) composites

Charpy impact test

Higher ductility of the CF/PEEK specimen was shown, with values increasing with temperature. On the CF/Epoxy side, overall lower ductility was observed, and the value dropped with increasing temperature observed in the CF/Epoxy specimens. In addition, weight-falling tests have shown that CF/PEEK specimens absorb more energy than CF/Epoxy in both elastic and plastic ranges.

Relative humidity absorption

CF/PEEK specimen reached after 48h the peak weight increase (0.14%) while the CF/Epoxy specimen showed a weight increase > 0.3% still unsaturated.

Recycling

Endless fiber-reinforced PEEK composite, as used in the Olimunllum sheets, can be recycled by chopping the old material, resulting in a composite with short fiber reinforcement that can be thermoformed again. The mechanical properties of pressed or injected CF/PEEK chopped compounds are significantly lower than the original endless fiber composite, but exceed those of new injection molded compounds.[1]

References
  1. Zepf, H.P.: Faserverbundwerkstoffe mit thermoplastischer Matrix, Expert Verlag, 1997
  • Niederstadt, G.: Ökonomischer und ökologischer Leichtbau mit faserverstärkten Polymeren, Expert Verlag, 1997
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