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Flame Retardant Fiber

Compared with ordinary fibers, flame-retardant fibers have significantly reduced flammability, and their burning rate is significantly slowed down during the combustion process, and they can quickly self-extinguish after leaving the fire source. Alfa Chemistry offers flame retardant fiber products to meet specific needs.


  • Intrinsic flame-retardant fibers mainly include inorganic fibers and organic high-performance fibers, of which inorganic fibers include basalt fibers, glass fibers, quartz fibers, boron fibers, ceramic fibers, etc.; organic high-performance fibers include aramid fibers, polyimide fibers, poly Phenyl sulfide fiber, aramid sulfone fiber and polytetrafluoroethylene fiber, etc.
  • Modified flame retardant fibers mainly refer to fibers with good flame retardant properties obtained by physical or chemical modification, such as flame retardant polyester, nylon and cellulose fibers. The main preparation methods include copolymerization chip spinning method, blended spinning method, composite spinning method, and so on.

Comparison of flame retardant properties of common fibers

The limiting oxygen index (LOI) refers to the minimum oxygen volume fraction required for the sample to maintain a complete combustion state in a mixture of oxygen and nitrogen. The higher the LOI, the harder the material is to burn. According to the limiting oxygen index (LOI) value of the fiber, it is generally believed that the oxygen index of flammable materials is<22, 22="" the="" oxygen="" index="" of="" combustible="" materials="" is="" between="" and="" flame-retardant="">27. The LOIs of common fibers and flame retardant fibers are shown in the table below.

LOI values of common fibersLOI values of flame retardant fibers
Cotton fiber18.0flame retardant PAN fiber27
Acetate fiber17.0flame retardant PET fiber28
PAN fiber18.5PVC fiber35
Polyester fiber23.5flame retardant PP fiber25
Nylon fiber22.0Phenolic fiber50
Silk23.0Polysulfonamide (PSA) fiber33
Wool24.0Polybenzimidazole (PBI) fiber40

Flame Retardant Mechanism

The flame retardant mechanism is to try to hinder the thermal decomposition of the fiber, inhibit the generation of flammable gas and dilute the flammable gas, change the thermal decomposition reaction mechanism (chemical mechanism), block the thermal feedback loop, and isolate the air and thermal environment, thus to eliminate or reduce the influence of the three elements of combustion (combustible substances, temperature, oxygen) to achieve the purpose of flame retardant. Generally, the mechanism of fiber flame retardant includes endothermic effect, covering protection effect, gas dilution effect, surface effect of particles and droplet effect.

Research Information

With the continuous development of flame retardant technology, innovative flame retardant fibers are being researched and developed. The current development trend of flame retardant fibers includes but is not limited to long-term environmental protection type, functional composite type and green environmental protection type. For example, Shuheng Liang et al. proposed a simple and effective method to improve the flame retardancy of blended fibers based on the synergy between flame retardant fibers. In this work, flame retardant viscose (FRV) was blended with three nitrogen-containing intrinsic flame retardant fibers (NIFRF), respectively. The prepared FRV/poly(isophthalamide) (PMIA) fibers exhibited excellent flame retardancy with an LOI as high as 47.5%. [1]

Research Information


  1. Shuheng Liang, et al. Cellulose, 2020, 27, 6083–6092.

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