Study On Synthesis Of Cyclodextrin - Containing Acrylamide Polymer Acid Thickener

According to research status of acid thickening agent and P-cyclodextrin characteristics, P-cyclodextrins which had vinyl double bonds was designed and synthesized. Then the acid thickening agent tetrapolymer (PAADM) was synthesized by acrylamide (AM),2-methyl-2-propenyl propionic acid amide (AMPS) and diallyl dimethyl ammonium chloride (DMDAAC) with aqueous solution polymerization process.Maleic anhydride (MAH) and β-cyclodextrin (β-CD) were chosen to synthetize vinyl β-cyclodextrins monomer (MAH-β-CD) with alcoholysis reaction. The optimum conditions were determined by single factor experiments:N, N-dimethyl-Formamide(DMF)was solvent, the ratio between solute and solvent was1g:3mL, molar ratio of monomer n(MAH):n(β-CD) was10:1. temperature of reaction was90℃, reaction time was5h. The results of the IR, UV and1HNMR confirmed the structure of the product was consistent with the original design.By orthogonal and single factor experiment determined the polymerization conditions of PAADM. The optimum experimental condition were as follow:mass ratio of monomer m(MAH-β-CD):m(AM):m(AMPS):m(DMDAA) was1:69:20:10, dosage of initiator was0.4%(ammonium persulfate and sodium bisulfite mass ratio of2:1), the reaction temperature was45℃, the monomer concentration of20%, the polymerization reaction continues6h, pH was7-8. The structure of PAADM was characterized by IR, UV and1HNMR.Acid thickening agent PAADM had good thickening, anti-temperature, anti-shear, retarder and compatibility. PAADM could soluble in hydrochloric acid in100min, the viscosity of system reached36mPa-s at170s-1when the hydrochloric acid was20%, the amount of PAADM was0.8%and the corrosion inhibitor was0.5%. The thermal stability rate of PAADM could separately reach87.5%and79.17%under60℃and90℃. And the anti-shear stability could reach83.33%at25℃. The retardation rate could reach42.29%,35.33%,30.38%when the temperature was separately30℃,60℃,90℃. Mixed with other additives under90℃for24hours, the PAADM solution didn’t have any sediment. The optimum formula for thickening acid was that the hydrochloric acid was20%, the amount of acid thickening agent PAADM was0.8%, the corrosion inhibitor WD-11was0.5%, clay stabilizer WD-5was0.3%, ferric ion stabilizer WD-8was0.5%and clean up agent WD-12was0.5%.When the concentration of hydrochloric acid was20%, the amount of thickening agent was0.8%, the crosslinking agent was20%(based on the amount of thickening agent, zirconium acetylacetonate and glutaraldehyde ratio of1:1), the crosslinking temperature was70℃, the system could reach750mPa-s when the shear rate was344s-1. The retardation rate could reach60%and the acid sludge was less than2%at60℃for1h.