Microcrystalline cellulose, starch, methyl cellulose, chitin, and polyacrylamide have been studied by differential scanning calorimetry and thermogravimetry. The thermograms of these polymers in the temperature range of 20–200°С display endothermic peaks describing the process of destruction of hydrogen bonds. The endothermic process is accompanied by mass loss associated with desorption of water from the samples. Adsorbed water plays a major role in the formation of hydrogen bonds in the polymers. The polymers and their mixtures were subjected to plastic deformation under a pressure of 2 GPa in an anvil type high-pressure device. As a result of this treatment, the enthalpies of endothermic processes in individual polymers increased by a factor of 2.8, but decreased in the polymer blends. In the deformed blends of microcrystalline cellulose with polyacrylamide, up to 36% of cellulose became water-soluble. According to its effect on cellulose, polyacrylamide can be compared with malonic acid.