Investigation of changes in the viscosity properties of acrylamide (co)polymer and their hydrolyzed forms depending on the conditions of their preparation

The synthesis of polyacrylamide and a copolymer of acrylamide and maleic acid was studied depending on the pH, duration, temperature, and concentration of the redox system of the initiator. The process of alkaline hydrolysis of synthesized polymers has been studied. High-viscosity characteristics of polymer solutions were taken as the main criterion. To study the effect of pH, radical polymerization was carried out at pH values created by monomers in the system and in slightly alkaline and strongly alkaline media. It was found that with the participation of the initiating system, potassium persulfate and sodium sulfite in an amount of 0.1% of the mass of monomers in a 10% solution of acrylamide at a temperature of 40 & DEG;C and pH of about 2.2, after 3 h of polymerization, the highest yields of a high-molecular product are achieved. This product is characterized by polyacrylamide with a molecular weight of about 1000 kDa, and the proportion of oligomeric compounds in this mixture does not exceed 20%. To maintain higher yields of the copolymerization reaction of acrylamide and maleic acid, the process must be carried out for more than 4 h at a molar ratio of acrylamide and maleic acid of 7:1 and values of pH = 8.0-8.1. The resulting copolymer is characterized by molecular weight values of about 2500-2800 kDa. It was found that the hydrolysis of synthesized samples at a temperature of more than 80 & DEG;C results in an increase in molecular weight, which is associated with a decrease in the proportion of oligomeric compounds in the resulting mixture. Due to an increase in the average molecular weight and the transition of functional groups to carboxylate as a result of hydrolysis, their viscosity characteristics increase.

Automated summary

The synthesis of polyacrylamide and a copolymer of acrylamide and maleic acid was studied under various conditions. The alkaline hydrolysis process of the synthesized polymers was also investigated. It was found that the highest yields of a high-molecular product can be achieved through radical polymerization at a temperature of 40°C and pH of about 2.2. The copolymerization reaction of acrylamide and maleic acid required a longer duration and a molar ratio of 7:1, resulting in a copolymer with higher molecular weight values.