Stable crystalline cellulose III polymorphs

摘要

Novel cellulosic fiber with improved resistance to abrasion and increased permeability to chemicals characterized by highly stable crystalline cellulose III and cellulose IV forms is disclosed. Cellulose selected from either fiber, yarn, fabric, cotton, or mercerized cotton is treated with ammonia vapors at from about ambient to 140 DEG C. and from about 100 psi to 1700 psi for sufficient time to alter the interatomic planar distances and produce stable crystalline cellulose III polymorph. Crystalline cellulose III can also be immersed in ethylenediamine and then boiled in dimethylformamide to completely convert the III to cellulose IV.