Copolymerization Of Anionic Polyacrylamide Oil-displacing Agent

Hydrolysed polyacrylamide with a super-high molecular weight suitable for driving crude oil in reservoir is synthesized by copolymerization of acrylamide and sodium acrylate. In this article, these factors including the molar proportion of acrylamide and soldium acrylate, the monomer concentration, the temperature and the time of copolymerization, the oxidizer concentration, the reducing agent concentration, the chain transfer agent concentration and so on that affect molecular weight and solving velocity of polyacrylamide are studied and the mechanism of copolymerization are researched. The optimum parameters of copolymerization are obtained as follows: pH value of solution is 11.5, the monomer concentration is 30%, the oxidizer concentration is 0.1%, the reducing agent concentration is 0.1%, the molar proportion of acrylamide and sodium acrylate 7:3, the chain-transfer agent concentration 0.3%, metal-shelter agent concentration 0.09%. The initial reaction temperature is 35℃. After comonomers react in the obturator for 2.5 hours, reaction temperature is hoisted to 55℃ for 3 hours. After the copolymerization, the polymer we obtained was dried at 80~90℃ for 20 hours. We can acquire the dry polyacrylamide. The super-high molecular weight polyacrylamide is obtained by using this process, with molecular weight 2.0x107 and soluble time 16 hours , hydrolytic degree being adjusted from 20% to 30%.