AM/AMPS/D I CSynthesis Of 12 AM/VTS-SiO 2 And Its Solution Properties

To solve the problem of poor temperature tolerance and salt resistant ability in application,a hydrophobically associating polyacrylamide(AM/AMPS/DiC12AM/VTS-SiO2)was synthesized by nano-SiO2 modified with Vinyltriethoxysilane(VTS-SiO2),a polymerizable monomer with two tails of long alkyl chain(DiC12AM),2-acrylamido-2-methylpropane sulfonic acid(AMPS),and acrylamide(AM)through free radical micellar polymerization.And its molecular structure was characterized by infrared spectrum and 1H NRM.Single factor optimization was adopted to obtain the best synthesis condition,which is that the doasge of AM,AMPS,VTS-SiO2,DiC12AM,OP-10 was 78 wt%、18 wt%、0.4 wt%、3.1 wt%、0.5 wt%of the total monomers mass respectively;2,2’-azobis[2-methylpropionamidine]dihydrochloride(V-50)was used as initiator and its dosage was 0.12%of total monomers mass;the concentration of monomers was 25 wt%;the pH of the system was 7;the reaction temperature and time was 40 ℃ and 8 h,respectively.Under this condition,the conversion rate of monomers was 97.35%,the intrinsic viscosity,viscosity-average molecular weight,and critical association concentration of AM/AMPS/DiC12AM/VTS-SiO2 were 840.16 g/mL,3.9×106 g/mol,and 3.8 g/L respectively.In addition,AM/AMPS/DiC12AM/VTS-SiO2 has thickening ability than high molecular(1.8 X 107 g/mol)HPAM at high concentration.The effect of functional monomer addition on the performance of polymer solution was investigated and the results of thermal experiments,salt experiments,and shear experiments showed that AM/AMPS/DiC12AM/VTS-SiO2 had the highest retention viscosity and fastest elastic response when the dosage of AMPS.DiC12AM、VTS-SiO2 was 18 wt%,3.1 wt%,0.42 wt%,respectively.The contrastive study on the solution properties of AM/AMPS/DiC12AM/VTS-SiO2 and HPAM was carried out.The temperature esperiments showed that AM/AMPS/DiC12AM/VTS-SiO2 has better temperature-tolerance ability than HPAM.At 90℃,the viscosity value and retention rate of 2 g/L of its solution was 607.4 mPa·s and 61.3%;the correlation value of 5 g/L of its solution was 2682 mPa·s and 63.8%;after aged for 30 days,the correlation value of 5 g/L of its solution with 100 g/L NaCl was 95.7 mPa·s and 29.2%.The salt experiments showed that AM/AMPS/DiC12AM/VTS-SiO2 has better salt-resistance ability than HPAM also especially at high concentration.At 25 ℃,when the solution contained 100 g/L NaCl,10 g/L MgC12,and1O g/L CaC12 respectively,2 g/L of its solution has 4 times、8 times and 13 times of retention rate than HPAM;Besides those will increase to 10,13,and 12 when the concentration increase to 5 g/L.In shearing experiments,AM/AMPS/DiC12AM/VTS-SiO2 shows better shearing resistance and recovery properties.Its viscosity was always higher than HPAM with the shearing rate increasing from 0 s-1 to 1300 s-1.After shearing for 5 min at 500 s-1,its solution viscosity basically unchanged.Moreover,small amplitude dynamic shear test reveal that AM/AMPS/DiCi2AM/VTS-SiO2 has a better visco-elastic property than HPAM.