Preparation And Research Of Polyacrylamide Copolymer Based On Double Carboxylic Anionic Monomer

Polyacrylamide(PAM)is a homopolymer of acrylamide(AM),a copolymer of AM and other ionic monomers,and a general term for the derivation of polyacrylamide.Polyacrylamide(PAM)has attracted wide interest in practical application because of its simple separation performance and multiple advantages of molecular double bond modification.In fact,although acrylamide functional groups tend to be single and aggregate,acrylamide shows low performance,but due to the abundance of ionic groups and tunable molecular structure,some organic polymers are good choices for acrylamide modification,thus widely used in a variety of fields,including water treatment.Carboxylate anions have a strong affinity for heavy metal ions and cations.In order to enhance the affinity of anionic monomers,carboxylic acid-rich functional monomers are introduced with easy copolymerization to form carboxy-rich polymer chains,which are highly hydrophilic and can form hydrogen bonds with the corresponding groups.The compound initiation system was adopted and the method of aqueous solution polymerization was selected.In this paper,a dicarboxylic vinyl organic monomer—2-acrylamidoglutaric acid(APA)was synthesized from glutamic acid as raw material for modification of polyacrylamide.The influences of initiator dosage,unit concentration,pH value and other factors on the polymerization process and the intrinsic viscosity of the product were investigated by single variable method.The production process was provided by F.R.and ~1H-NMR,and the products P(AM-APA)and P(AM-DAC-APA)were applied to the simulated sewage flocculation test in the laboratory.The specific content is as follows:Firstly,non-ionic polyacrylamide PAM was prepared by homopolymerization of AM initiated by the composite initiation system,and the influence of various conditions on the polymerization process was discussed.The optimal process was obtained by many experiments:The optimal concentration of REDOX initiator is0.025%,the optimal molar ratio of reducing agent to oxidizer is 1:10,the optimal dosage of V-50 is 0.1%,and the intrinsic viscosity is above 18.72 d L/g(molecular weight is 1.325×10~7g/mol)under the condition of high pH value of 7-8.The anionic functional monomer APA was synthesized by two steps.Through the analysis of FT-IR and ~1H-NMR,it can be seen that the prepared non-ionic PAM products and anionic functional monomer APA are obtained.Secondly,AM and APA monomers were used to obtain P(AM-APA)through binary copolymerization of composite initiation system.The influence of various conditions on the polymerization process was systematically explored,and the optimal polymerization process was obtained as follows:The optimal concentration of REDOX initiator is 0.025%,the optimal molar ratio of reducing agent to oxidant is6:10,V-50 in monomer mass fraction is 0.1%,monomer concentration is 25%,APA dosage is 3%of monomer molar mass,and the intrinsic viscosity is above 7.26 d L/g(molecular weight is 3.15×10~6g/mol)under the condition of high pH value of 4-5.Through FT-IR and ~1H-NMR analysis,it was proved that the anionic functional monomer APA had been successfully connected to the main chain of PAM,and the anionic polymer P(AM-APA)was prepared.In the flocculation test using kaolin as the simulated liquid of suspended sewage,the double-carboxylic anion polymer P(AM-APA)has better performance than the single-carboxylic anion polymer P(AM-AA),which can achieve better flocculation effect and acid resistance at less dosage,and the light transmissions of its supernitants are more than 96%,respectively.Finally,choose the method of aqueous solution polymerization to AM,DAC,APA as monomer,the reaction is obtained by composite initiator system ternary copolymer P(AM-DAC-APA)system study of the influence of various conditions on the polymerization process,to get the best polymerization process,optimization of REDOX initiator concentration was 0.020%,reducing agent and oxidant optimum molar ratio of 1:1,V-50 accounted for 0.1%of monomer mass fraction of monomer concentration was 25%,the functional monomers for 10%of monomer molar mass and DAC:When APA molar mass ratio is 9:1,initial temperature is preferably 5°C,and pH value is 5-6,the intrinsic viscosity is above 8.49 d L/g(molecular weight is3.99×10~6g/mol).Through FT-IR and ~1H-NMR analysis,it was proved that functional monomers DAC and APA had been successfully connected to the main chain of PAM,and amphoteric polymer P(AM-DAC-APA)was prepared.The amphoteric polymer P(AM-DAC-APA)has excellent performance in the flocculation test using kaolin as the simulated liquid of suspended sewage.Under acidic conditions,the light transmittance of the superliquid reaches more than 90%,respectively.