As for bamboo batting, I get so irritated that they call it bamboo! It is rayon. Rayon, rayon, rayon. Whew. I feel better.
But rayon made from bamboo. This from wikipedia:
Rayon is a manufactured regenerated cellulose fiber. It is made from purified cellulose, primarily from wood pulp, which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in fibers of nearly pure cellulose.
Cellulose from bamboo is suitable for processing into viscose rayon. Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted using a steaming process and then mechanically crushed.