I am interested in building an experimental lubricant-less pneumatic tube system in which the canister will be propelled up to a high-velocity, reaching a peak velocity of approximately 100 m/s before the canister is forced to slow down and come to a stop.
The canister should attain a high velocity within the pneumatic tube by being propelled by ambient air pressure behind it and there being very low air pressure in front of it inside the tube (similar to the Hyperloop). I plan to create this very low air pressure either through the use of a vacuum pump, or perhaps by sealing one end of the tube with tape and then pulling the canister backward through the entire tube and then releasing it.
I have spent time researching on the Internet for what would be an ideal material to use for the O-rings that will wrap around this canister. The challenge I'm facing is trying to find O-rings that will keep the ambient air pressure from leaking around the canister and getting into the tube, and at the same time being slippery enough to glide over the tube's internal surface, whether the tube is made out of metal or PVC.
I have the option of putting standard rubber O-rings around the canister, yet this would require me to lubricate the pneumatic tube with some type of grease/oil before each test and I don't wish to lubricate several hundred feet of tubing for each test.
I have considered making the felt-covered, rubber O-rings, yet I think a lot of air may push through the felt. I have also considered making O-rings out of tightly wound silk, yet I think silk O-rings will not last very long. So, I am seeking suggestions on what would be an ideal material to use for these special-purpose O-rings.
What would be an ideal material to use for O-rings on a canister in a lubricant-less, high-velocity pneumatic tube system?