Teflon tape can be used on any type of liquid joint. However, it is strictly speaking a lubricant, NOT a sealant, and is a cheap and nasty way of sealing joints. - The proper sealant for any liquid pipe joint is a pipe joint compound such as Whitlam's or Oatey's Blue Joint Compound.
Approved pipe joint compounds
plastic
Plastic pipe is both affordable and durable, so using it for new plumbing is a good idea.
Yes , plastic is a poor conductor of heat!!:) Metal is a good conductor though
Pipe sealant that is often used as a boiler repair by Hercules chemical corp
Only apply thread sealant to the MALE threads of the pipe.
No, teflon tape is not sticky and that's for a good reason. -Most people think of teflon tape as a sealant. However it was originally intended for plumbing use as a sealant AND a lubricant so you can get a tighter connection on the pipe joint.
It depends on the thickness of the plastic pipe. :)
No, not a good idea. Best to get a replacement.
Teflon tape is good. There is now a teflon liguid sealer also. The old pipe sealer is still good. I used a piece of radio solder last year to seal a water meter joint when I lost the meter seal. Be inventive.
Cut the pipe and remove it, fix pipe with a coupling.