Investigation of the state of water sorbed by an organic polymer by high-resolution1H nuclear magnetic resonance and differential thermal analysis

Conclusions The results of the experimental investigation of a moist organic composite by high-resolution NMR and DTA indicate a change in the structure of water, due to an interaction between the water molecules and the macromolecules when water is sorbed by the organic polymer. A part of the sorbed water molecules is strongly bound to the macromolecules; their mobility is very low and is not recorded by high-resolution NMR. As the moisture content of the composite increases, molecules of water appear, the mobility of which is intermediate between the strongly bound and free water molecules in the macrospace. This part of the molecules is represented in the NMR spectrum by a broadened and shifted line and a shift of the endothermic peak towards lower temperatures is observed on the thermal analysis diagrams. The weakly bound water can be detected in the composite starting at a moisture content of 5–8%.Translated from Mekhanika Kompozitnykh Materialov, No. 2, pp. 317–320, March–April, 1990.