The floss found in milkweed pods, shaped like a tube, consists of a hollow cellulosic fibre with thin walls which account for only approximately 10% of its total diameter. This particularity provides important advantages in regard to absorption. The fibre not only traps on its surface but also inside.
From an acoustic stand point, these micro tubes of air act as barriers against sound. From a thermal perspective, maintaining empty micro volumes of almost still air greatly diminishes heat exchanges to a point where it amounts to goose down performance, the reference in insulation.