Dependence of the viscoelastic properties of cellulose on water content

The dynamic mechanical properties at about 1 Hz of a film of regenerated cellulose have been measured over a range of temperatures from −100 to +90°C and water contents from effectively zero to 3%. Three loss peaks were found which were attributed to molecular motions in the amorphous regions. One of these was postulated to involve motion of segments of two chains connected through hydrogen bonding via a “tightly bound” molecule of water. Viscoelastic measurements over a somewhat wider range of water contents at room temperature exhibited contradictory effects depending upon the amount of water. These results provide support for the concept of two types of water in cellulose: tightly bound and loosely bound.