Hi
I have a need to remove a long tube of PTFE even in destructive means
Is there any chemicals or process which could convert physical properties of PTFE into non solid form - ie powder liquid or gas?
Yes, the laser will create toxic fumes. The same is true with pyrolysis- all you're changing is the heat source. High temperature steam decomposition will generate mostly tetrafluoroethylene, which itself isn't that toxic, but it will also generate some HF, CO and other molecules depending on the temperature and how much oxygen comes along for the ride with the steam.
Sodium will defluorinate it, and will make it crumble into dust. The resulting compounds aren't toxic, but sodium is dangerous to handle. I'm not sure why the defluorination causes the PTFE material to lose coehsion but it certainly seems to.
Consider a thermite flare reaction 2Mg + (C2F4) ⟶ 2MgF2 + 2C, this similar mechanism could be possible with sodium. If you go the sodium route, just be ready for a HIGHLY exothermic reaction.
I was thinking that if the tube is large enough and straight, it might be possible to run a trepanning cutter through to remove most of it mechanically.