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Hebei Carbon Valley Carbon Fiber Co., Ltd

Manager Hao (pre oxygenation thread): 13831164999

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Manager Zhao (woven fabric, pre impregnated fabric, prefabricated body): 15028196018

Manager Zhang (woven fabric, axial fabric): 13703314888

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Address: 226 Shifu East Road, Gaocheng District, Shijiazhuang City, Hebei Province

细河区What is the purpose of pre-oxidation treatment for pre-oxidized fiber?

2026-01-10 14:39:01

15124

The core purpose of pre-oxidation treatment for precursor filaments (the key step to produce pre-oxidized fiber) is to transform thermoplastic precursor materials into thermoset fibers with stable chemical structures, so as to avoid melting, sticking or decomposition of the filaments during subsequent high-temperature carbonization and graphitization, and lay the foundation for manufacturing high-performance carbon fibers.

Specifically, the purpose can be broken down into four key aspects, which are closely linked to the quality of the final carbon fiber:

Prevent melting and bonding during high-temperature processingPrecursor filaments (especially PAN-based and pitch-based ones) are thermoplastic—they will soften and melt when heated directly to high temperatures (above 1000°C for carbonization). Pre-oxidation introduces oxidation cross-linking reactions, turning the linear molecular chains of the precursor into a rigid, three-dimensional network structure. This makes the fibers lose thermoplasticity and become thermoset, so they won’t stick together or deform in the follow-up high-temperature processes.
Build a stable carbon-rich molecular frameworkDuring pre-oxidation, a series of chemical reactions occur inside the precursor filaments: cyclization of PAN molecular chains, dehydrogenation, and oxidation cross-linking. These reactions remove unstable small molecules (such as water, ammonia) and form conjugated double bond structures with high carbon content. This stable framework can withstand the high-temperature pyrolysis in the carbonization stage, reducing the loss of carbon elements and ensuring the final carbon fiber has a high degree of crystallinity and mechanical strength.
Improve the mechanical properties of the final carbon fiberIn the pre-oxidation process, proper tension is applied to the filaments to align the newly formed molecular chains along the fiber axis. This oriented structure is retained and strengthened in the subsequent carbonization and graphitization steps, which directly improves the tensile strength and modulus of the final carbon fiber. If pre-oxidation is insufficient, the molecular chains will be disordered, leading to a sharp drop in the mechanical properties of the carbon fiber.
Enhance the processability of the fibersPre-oxidation adjusts the density and surface properties of the fibers, making them have appropriate toughness and rigidity. This allows the pre-oxidized fibers to be smoothly wound into rolls, transported, and fed into the next production line without being easily broken. Meanwhile, the oxygen-containing groups formed on the fiber surface during pre-oxidation also lay a good foundation for the subsequent surface treatment (to improve the bonding force with resin matrix).

For different precursors, the focus of pre-oxidation will be slightly adjusted: for example, PAN-based precursors focus on cyclization and dehydrogenation, while pitch-based precursors pay more attention to controlling the oxidation degree to avoid excessive structural damage.

Carbon Fiber,Pre-oxidized Fiber,Carbon Fiber Prepreg