Preparation of Copolymer of Dihydroxy Monomer and Acrylamide and Its Solution Properties with Polyphenylboronic Acid Compounds

Graphical When the DPMOH 2 content in P(AM-DPMOH 2 ) exceeded 40 wt%, M η of P(AM-DPMOH 2 ) was higher than 5.0×10 5 g/mol, molecular weight of PEI in BPEI was larger than 3000 g/mol, the content of phenylboronic acid groups in BPEI was more than 39.3 %, and the pH was in the range of 8–10, the thickening composite system can be formed by P(AM-DPMOH 2 ) and BPEI in water. When the pH was in the range of 7–8, intramolecular crosslinking of P(AM-DPMOH 2 ) was dominant and the viscosity was decreased. When the pH was smaller than 7, the boronic ester bond was hydrolyzed and the thickening effect lost. : The construction of composite flooding system based on dynamic covalent bonds is one of the effective methods to improve the salt and temperature resistance of polymer flooding agents. The polymers used in most composite systems are xanthan gum and guar gum. In this paper, a novel multi-hydroxyl polymer was synthesized, and a new composite system was constructed based on the dynamic boronic ester bonds. Firstly, the multi-hydroxyl polymer P(AM-DPMOH 2 ) was prepared by aqueous solution copolymerization of acrylamide (AM) and a dihydroxy monomer 2,3-dihydroxy-N-(3-methacrylamidopropyl)-N,N-dimethylpropan-1-aminium (DPMOH 2 ), which was obtained by quaternization reaction between 3-chloro-1,2-propanediol and N-(3-dimethylaminopropyl). Then, the composite system was prepared by the P(AM-DPMOH 2 ) solution and polyboronic acid compound (BPEI). The effects of DPMOH 2 content in P(AM-DPMOH 2 ), molecular weight of P(AM-DPMOH 2 ), molecular weight of BPEI, phenylboronic acid groups content in BPEI and pH on the formation of thickening composite system were investigated. The results showed that when the content of DPMOH 2 in P(AM-DPMOH 2 ) exceeded 40 wt%, viscosity average molecular weight of P(AM-DPMOH 2 ) was higher than 5.0×10 5 g/mol, the molecular weight of PEI in BPEI was larger than 3000 g/mol, the content of phenylboronic acid groups in BPEI was more than 39.3 %, and pH was in the range of 8–9, the thickening composite system can be formed by P(AM-DPMOH 2 ) and BPEI. In addition, both the temperature and salt resistance of the composite system formed by 3000 mg/L P(AM-DPMOH 2 ) and 2000 mg/L BPEI was much better than that of 3000 mg/L P(AM-DPMOH 2 ). The results of this paper provide a new finding of how to construct a composite flooding system with dynamic covalent bonds.