Oxidized Polyacrylonitrile fiber

PREOX fibers are produced on the basis of polyacrylonitrile and form an intermediate stage in the production of carbon fibers. Oxidative treatment at 200-300°C produces very temperature-stable, non-melting/dripping and, above all, non-combustible fibers. The fibers are therefore ideally suited for fire protection applications.

Pros and cons
Oxidized Polyacrylonitrile fiber Properties


  • Non-flammable
  • Does not melt
  • Flame retardant
  • High LOI value well over 40%
  • High UV resistance and chemical resistance


  • Black inherent color
  • Relatively low strength and elongation

Oxidized Polyacrylonitrile fiber
Manufacturing process

To produce PREOX fibres, acrylonitrile is polymerized in a first step and then spun into PAN fibres. The properties of the resulting PREOX fibers can be significantly influenced by the right choice of co-monomers, spinning technique and degree of stretching. In the next step, the PAN fibers are oxidatively treated at 200-300°C to produce finished PREOX fibers. This treatment step, also known as stabilization in carbon fibre production, comprises two sub-steps. A cyclization reaction of adjacent acyl nitrile units forms a ladder polymer structure, which is further stabilized by dehydrogenation in the subsequent reaction process. Depending on the area of application, the fibers also receive a suitable surface treatment after production. 

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technology and
quality of the fibre

State-of-the-art laboratory facilities, quality management according to ISO 9001:2015, energy management according to ISO 50001:2018 and last but not least the high demands on our own work ensure the high quality standards of our Oxidized Polyacrylonitrile fiber. See for yourself.

If you want to know more about the technology and quality of our Oxidized Polyacrylonitrile fiber If you want to know, just get in touch with us. We would be happy to advise you comprehensively and help you with our know-how.

You are looking for the perfect Oxidized Polyacrylonitrile fiber for your application or have an exact requirement profile, which the used Oxidized Polyacrylonitrile fiber must fulfill?

Then you are exactly right, as a technology leader in the field of fibre development and production, we offer you individual solutions and manufacturing processes that ensure constant and reproducible fibre quality.



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