Chemical properties Polyacrylamide is relatively stable to heat, its solid is softened at 220 ~ 230℃, and its aqueous solution is degraded significantly after 110℃. Polyacrylamide is insoluble in benzene, toluene, xylene, gasoline, kerosene, diesel, but soluble in water. Polyacrylamide reacts with a base to produce partially hydrolyzed polyacrylamide, which produces imidation at strong acidity (pH≤2.5), reducing its solubility in water. It can be cross-linked to the polynuclear hydroxyl bridging ions of aldehydes (such as formaldehyde) and high-priced metals (such as aluminum, chromium, zirconium, etc.), and is easily degraded by mechanical and/or oxygen action. In oil production, it is mainly used as oil displacement agent, water blocking agent, profile control agent, viscosifier, resistance reducing agent, water treatment agent and so on. Physical properties Solubility in water: under mechanical rapid agitation, it is easily dissolved in cold water to form a transparent adhesive solution. Increasing the temperature does not affect its solubility, and its dissolution is limited only when the concentration of the solution increases to a high viscosity. Solubility in other solvents: more than 1% solubility in solvents such as glycerin, ethylene glycol, formaldehyde, acetic acid and lactic acid (these substances can be used as plasticizers for polyacrylamide coatings). In propionic acid, propylene glycol and other solvents can only swell but not dissolve, can not dissolve in acetone and hexane and other solvents. Stability: It has a moderate degree of hygroscopicity and can be stored in powdered form for a long time if it is not exposed to extremely high temperature Chemicalbook. For liquid polyacrylamide, when its concentration is greater than 17%, it can be stored for more than one year, and the solution viscosity does not change significantly. In the range of pH value 3 ~ 9, can maintain a good stability; At higher pH, there is a gradual increase in viscosity. Miscibility: at commonly used concentrations, miscibility with most natural or synthetic water-soluble resins, most latex systems, and most salts. It is also rapidly miscible with non-ionic, cationic, and anionic surfactants, but some surfactants may affect its viscosity. Viscosity: The viscosity of polyacrylamide solution has a linear relationship with its molecular weight, in addition, the higher the temperature, the lower the viscosity. Intrinsic viscosity: As the molecular weight increases, the intrinsic viscosity increases. Ionic: Long chain with carboxyl group is anion type, with amine group is cationic type. Because polyacrylamide has carboxyl or amine groups on the long chain, it is easy to flocculate when it encounters aluminum ions. Retention: The retention trend of polyacrylamide and soap rosin is consistent, but the retention rate of the former is high. Toxicity: Polyacrylamide itself is not toxic, but it is toxic to the human body if it contains monomers that have not been polymerized (with double bonds). At the end of production, a certain amount of sodium bicarbonate should be added to remove the remaining monomer.
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