Multizone oxidation technique
The thermo-oxidative stabilization process is the first stage in the heat treatment line. The process is the rate limiting step in the entire heat treatment line, owing to the exothermic nature of the process. During this process, the precursor tow band is introduced into a hot air recirculated isothermal chamber, wherein the hot air transfers the heat by flowing past the tow band. The fiber tow band passes through multiple hot air chambers, in multiple to and fro passes guided by a system of driven rollers and idler rollers in sequence. The fibers undergo stabilization reactions under a controlled temperature profile, in the presence of atmospheric oxygen, and are subsequently introduced into the pre-carbonization furnace. The stabilized fibers are infusible and flame retardant and hence used to weave fire-resistant fabric.
Maximum precursor tows: 40
No of isothermal chambers: 4
Line speed: Max 1.5 m/min
Temperature : Max 300oC
Facilities where this techniques is used : Fiber heat treatment facility (F3)
Major mile stones / results of this technique : Certification for standard modulus grade carbon fibers