Moisture regain measurements have been made at 25° C. and 79.3% relative humidity on non-acetylated and acetylated fibroin.
The equilibrium moisture content of acetylated fibroin is slightly lower than that of non-acetylated fibroin and varies with the degree of acetylation.
In the case of fibres acetylated by the action of acetic anhydride it is shown that the decrease in moisture content is not attributable to the action of liberated acetic acid.
