Isophase Transitions of Cellulose – A Short Review

Cellulose has a complicated supramolecular structure consisting of nanofibrils, which are built of ordered crystallites and low ordered noncrystalline domains. In this critical review, isophase temperature transitions in noncrystalline domains of cellulose were described and discussed. It has been shown that due to structural heterogeneity the noncrystalline domains have three isophase temperature transitions, where the α1 and α2 transitions are caused by the occurrence of segmental mobility in dense mesomorphous and medium packed amorphous clusters, respectively; whereas the β transition is related to the mobility of small segments in loose packed amorphous clusters, which probably are located on the outer surface of nanofibrils. Under the action of water and other plasticizers all three isophase transitions are shifted to lower temperatures.