A DSC Study of the Endothermic Process, Associated with Hydrogen Bonding, in Polysaccharides after High-Pressure Plastic Deformation

• Published in: High energy chemistry Vol. 54; no. 4; pp. 263 - 269
• Main Authors: Zhorin, V. A., Kiselev, M. R.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.07.2020; Springer Nature B.V
• Subjects: Cellulose; Cellulosic resins; Chemistry; Chemistry and Materials Science; Chitin; Crystalline cellulose; Endothermic reactions; Enthalpy; Hydrogen bonding; Hydrogen bonds; Mechanochemistry; Physical Chemistry; Plastic deformation; Polyacrylamide; Polymer blends; Polysaccharides; Thermogravimetry; polysaccharides; cellulose; hydrogen bonds; high pressure; plastic deformation
• ISSN: 0018-1439; 1608-3148
• DOI: 10.1134/S0018143920040141

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.