I have been making electrospun fibers using PAN on a stationary collector. We have been carbonizing the sheets to use as a substrate but after the carbonizing the sheets become brittle and have been difficult to use for our other testing.

Is there a way to make them less brittle?

The SEM image is is the after of the current carbonization process and it looks good as I want. Mounting them in the test holder and handling them is difficult. Would making thicker sheets to start with before I carbonize them make them less brittle?

Heating profile is below:

10 degree ramp for 30 minutes to 300 C

300 minutes at 300 C (air)

20 degree ramp for 25 minutes to 800 C

120 minutes at 800 C (argon)

I think the PAN fibers carbonize around 300 C to begin with and the higher temp is to stabilize them.

Thanks for any suggestions to improve the process.