Crystalline Structures of Cellulose Dinitrates and Their Saponification Products Derived from Various Crystalline Modifications of Cellulose

Abstract

Crystalline structures of cellulose dinitrates and their saponification products derived frem various crystalline modifications of callulose were studied by means of X-ray diffractien method.
All cellulose dinitrates, derived from any crystaHine modifications of cellulose and recrystallized with s er heated water, gave the same X-ray diffractgraph. Different from trinitrate, there was not found crystalline modification of cellulose dinitrate resulting from crystalline structure of original cellulose. Amorphous cellulose dinitrates, which were derived from cellulose I family(1, I and V I)and not recrystallized, were sap ified to cellulose I and renitrated to cellulose trinitrate I, while those derived from cellulose family(, and N ll)were saponified to cellulose Ir and renitrated to cellulose trinitrate. It was shown that before recrystallization molecular configuration of each family remaind unchanged during nitratien and saponification processes. Recrystallized cellulose dinitrates were saponified te cellulose g and renitrated to cellulose trinitrate irrespective of the crystalline structure f riginal cellulose. Therefore, the skeletal chain conformation in cellulose dinitrate crystallite would be bent and twisted form similar to that of cellulose family, but in amorphous dinitrates derived from cellulose 1 family the skeletal chain conformation retalned bent form and changed to bent and twisted form in recrystallization process.
In infrared spectrum of cellulose dinitrates stretching mode of OH groups showed parallel dichroism. lt was considered that unaltered OH groups in cellulose dinitrate were those adjacent to Cs position forming intramolecular hydrogen bonds.