<p>What materials, available as filaments for use in FDM printing, are known to be the most physically and chemically inert? In particular, stability (not necessarily simultaneously) in the presence of the following should be assumed:</p>

<ul>
<li>pH 0-14</li>
<li>oxidizing agents (ozone, permanganates, dichromates, acidic hydrogen
peroxide)</li>
<li>organic solvents (particularly acetone, methanol, toluene, formamide)</li>
<li>temperature up to 160 degrees Celsius</li>
<li>pressures between ~10^-7 torr and ~2 bar</li>
<li>oxygen or argon plasma</li>
</ul>

PEEK, a plastic known for its superior chemical and physical resilience (
http://www.zeusinc.com/materials/peek/chemical-resistance-chart-peek
), has been successfully used for filament-based printing (
https://3dprint.com/52713/indmatec-peek-fdm-printing-filament/
). However, it is unlikely to be an option on most existing printers given its high melting temperature (around 343 degrees Celsius,
https://en.wikipedia.org/wiki/PEEK
). Though it does not meet all the criteria proposed (for instance, its glass transition temperature is around 143 degrees Celsius), overall it is a fairly good choice.
Teflon, an obvious choice, unfortunately has a decomposition temperature very close to its melting temperature, and appears to be unsuitable for extrusion.