Structure of PAN Fibers Thermally Stabilized at

When examined by wide angle X-ray the diffractograms showed stabilized fibers to have an additional peak at 20= 13° due to a structural entity with 0.68 nm repeat units and the proposed structure is as shown. 

Mechanical properties of carbon fibers prepared from Courtelle PAN stabilized at temperatures 250°C-400°C and carbonized at 1000°C in N2 

Source Reprinted with permission from Mathur RB, Bahl OP, Mittal J, Nagpal KC, Carbon, 29(7), 1059, 1991. Copyright 1991, Eisevier. 

Noh and Yu [102] have stated that the disappearance of the nitrile groups is not complete, but reaches a final value of about 20% residual nitrile groups. 

Since O2 has to diffuse through and at one stage of the oxidation process, the diffusion rate ex Vtime, the filament diameter is limited to 10 pm in order to keep the oxidation time within commercial limits. 

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