A mechanism for hardening of phosphate materials and the role of hydrogen bonding in this mechanism has been considered. The adhesive properties of binding phosphate materials are discussed and factors affecting the buildup of adhesive bonds between the binding material and the hard surface of a substrate or particles of the filler are analyzed. Correlations between the properties of the binding phosphate material and the cohesive forces are considered.Inorganic binding materials, in particular those of phosphate origin, belong to a class of polyfunctional compounds. Binding phosphate materials for use in the production of refractories and castables have been studied in much detail [1,2]. Despite the wealth of domestic patent literature, the use of binding phosphate materials for production of corrosion-resistant coatings and mortars capable of providing a secure binding of parts and components into a monolithic structure has not received sufficient attention. In our opinion, this state of things has a simple explanation -until now, no reliable theoretical treatment of the very phenomenon of adhesion has been proposed. The adhesive interaction between contacting materials involves a range of physical factors of different nature, and their contribution to the buildup of adhesion bond has never been analyzed and discussed in sufficient detail. To date, a few models have been proposed; of these, the most popular are models of electrostatic and adsorptive phase interaction.An electrostatic model of adhesion proposed by Deryagin [3] is based on the concept of a double electric layer generated at the contact surface of two bodies owing to the directional adsorption of polar functional groups of an adhesive (a binding material after Deryagin's terminology). Polar functional groups displaying a large dipole moment are COOH, -OH, NH 3 , -CHO, and some others. The Deryagin theory provides a satisfactory description of the adhesive properties of organic polymer materials (cellulose, gelatin, natural rubber) applied from polar solvents onto the surface of glasses or metals. However, it fails to explain the adhesion of nonpolar materials, in particular, binding phosphate materials that are electric conductors to a significant extent (not dielectrics!) and, for this reason, are not capable of forming a double electric layer.The adsorption model is more versatile in this respect; it considers adhesion as a result of molecular interactions at the contact boundary. The molecular interactions involve dispersion forces (up to 30 kJ/mole), induction forces (up to 40 kJ/mole), and hydrogen-bonding (H-bonding) forces which may vary from 10 to 40 kJ/mole. Not infrequently, the strong H-bonding with the substrate was effected through participation of polarized molecules formed because of the large difference in electronegativity of cationic compounds. With reference to conclusions drawn in Part I [4], one can assert with certainty that the occurrence of an extended network in aqueous H 3 PO 4 solutions and the buildup of disordered glas...
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