THE STUDY ON THE MECHANISM OF CELLULOSE REACTION

(V) THE INVESTIGATION OF THE ACETYLATION

Abstract

On the previous paper, the new method by means of the infrared spectra had been developed for the study of the mechanism of celluose reaction. In the present report, the mechanism of the acetylation has been studied applying this new method with the birefringence and the X-ray diffraction method.
The following results were obtained:
1) On the infrared spectra method.
At the initial period on the acetylation, the accessibility of the hydroxyl group on the partially acetylated cellulose decreases. In spite of the proceeding of the acetylation, the spectrum-figures of the stretching mode which were originated in the unaccessible hydroxyl group on the partially acetylated cellulose are similar to the unreacted cellulose.
From these findings, it is considered that the acetylation has the selective reactivity on the amorphous region and the micro-heterogeneous property.
2) On the birefringence method.
The clear dual structure is observed on the cross-section of the partially acetylated film. From this finding, the macro-heterogeneous property for the acetylation is considered.
3) On the X-ray diffraction method.
At the initial period of the acetylation, the interferences of the partially acetylated cellulose are similar to the unreacted cellulose.
At the proceedings of the acetylation, the co-existence of the interferences which were originated in the unreacted cellulose and cellulose triacetate was observed. From these findings, the heterogeneous property of acetylation is considered.
On the basis of the above results, the mechamism of the acetylation is discussed.