Here is cutaway view of an Accubond ML sabot:
Most of my sabots for the ML are PVC type II which is corrosive due to small amounts of chlorine gas given off when fired! The bore needs to be cleaned and oiled after every shooting session as a result which is a pain....but these have been the most accurate for me.
If I were molding sabots then some sort of Nylon or PET or some combination would most likely be my choice. Since I machine each sabot individually, sawcut the petals, and debur by hand I need a very different set of specs for my sabot material.
You need a material that is strong enough to not blow a hole in the sabot, a material that is rigid enough to keep the bullet centered in the bore, and will separate cleanly from the bullet in a nearly identical manner every time.
There are two main types of sabots, one type stays intact like most soft ML sabots and open like a flower. The other type like mine and those used by the depleted uranium anti tank shells separate into pieces are made from very rigid material and these pieces carry a lot of energy.
The base of my sabot often travels a hundred yards and has about 400 ft/lbs of energy at the muzzle so you need to watch out for bystanders and ricochets!