Mechanism of transition between cellulose I and cellulose II during mercerization

It is suggested that the transformation from cellulose I to cellulose II during mercerization is the result of a progressive shift of the sheets of cellulose chains within the crystallites of a microfibril from the quarter‐staggered relation in cellulose I to complete correspondence in cellulose II. Qualitatively, the results of such a shift would be consistent with the observed increases in lateral disorder, changes in cell dimensions, swelling, changes in infrared absorption, increases in reactivity of hydroxyl groups and especially with changes in the relative intensities of meridional, x‐ray diffraction reflections of cellulose fibers. The consequences of such a shift also include variations of the dihedral angle at the glycosidic linkage to provide an opportunity for the conformational changes which have been deduced from Raman and infrared spectra. Such a shift may take place in the transformation of native celluloses with antiparallel structure as well as those with parallel polarity. It is consistent with and is able to explain examples of “memory” of previous treatment in cellulose samples.