Studies On The Synthesis And Properties Of Acrylamide-based Polymers

Acrylamide-based polymers are the names of acrylamide homopolymer and copolymersof acrylamide with other monomers. Polyacrylamide(PAM), an important water-solublepolyelectrolyte, is widely used as flooding agent for EOR, chemical engineering, flocculants,paper-making additives and so on in industry.The main purpose of this paper is to investigate the synthesis and properties of acrylamide-basedpolymers.A super high molecular weight HPAM and a cationic PAM, zwitterionic polymers withantipolyelectrolyte behavior in solution, temperature-tolerant and salt resistant tetrapolymer and a novelcomb-like zwitterionic PAM derivative were synthesized, their properties were evaluated.By using a complex redox initiating system composed of a self-made difunctional peroxide initiator,a reductive agent and a water-soluble azo-compound, a kind of PAM with ultra high molecular weight of≥3.0×107 were obtained under conditions: concentration of monomer 32%, concentration of difunctionalperoxide 10mg/L, azo 25mg/L,EDTA 60 mg/L,sodium formate5mg/L, urea 400 mg/L andpolymerization temperature 6℃ . The PAM was hydrolyzed in a microwave reactor at optimizedconditions and HPAM was obtained at expected hydrolysis degree with good solubility and molecularweight over 3.3×107. In core flooding experiments the enhancement in oil recovery by 800mg/L ofHPAM solution injected was of over 15%, higher than that of HPAM(DQ2500).By using a complex initiating system of persulfate, NaSF, functional monomer DA and additives,cationic PAM was synthesized with AM and AETMAC as co-monomers. The polymerization iscontrolled under low temperature(10℃ )in aqueous solution, concentration of initiator 60 mg/L, totalmonomer concentration 20%, pH 8, concentration of DA 600mg/L, urea 100mg/L,EDTA100mg/L,Span-20 100mg/L, azo 80 mg/L, the molecular weight of CPAM was over 1.0×107.Under experimentalconditions, the reactivity ratios of AM and AETMAC are caculated by means of three methods: F-R,K-T, and YBR., they were rAETMAC=0.3835,rAM=2.2863. Through the flocculation experiments ofusing Poly(AETMAC-AM) disposing of bentonite suspension and urban waste water, the optimumcapacity is determined. The result showed the flocculant has good solubility and flocculation efficiency.Its efficiency is better than other flocculants, and as good as products abroad.Three kind of betaine zwitterionsic monomers were synthesized and copolymerized with AM toprepare zwitterionic polymers with antipolyelectrolyte behavior in solution. The results showed that thethree zwitterionic copolymers in 1000～4000mg/L salt solution, their solution viscosity increased withthe concentration of salt. In core flooding experiments the enhancement in oil recovery by 1000mg/L ofthe polymers solution injected was of over 10%.The synthesis of a tripolymer of acrylamide(AM), 2-acrylamido-2-methylpropanesulfonic acid(AMPS )and N,N-dimethylacrylamide(DMAM) as raw material was gained byfree radical micellar copolymerization. The optimum conditions was attained by the methodof orthogonal test. Under the optimized conditions, the intrinsic viscosity of the tripolymerwas reached 22.0dL/g. With microwave hydrolysis technology, a tetrapolymer ofAM-DMAM-AMPS-AA copolymer was obtained with intrinsic viscosity reached about27.0dL/g. The structures of the copolymers were characterized by FTIR. Solution propertiesof the tripolymer and tetrapolymer were studied, and showed that the two polymers had goodsolubility, viscositying effect and significant salt resistance. Under conditions of temperature45℃ , shear rate 2000rpm, maintaining ratio of viscosity was over 90%, in aging treatment at90℃ in more than 30 days standing, their maintaining ratio of viscosity was over 85%. It wasfound that the effect of concentration of SDS on polymers solution viscosity was muchstronger.A new betaine-type zwitterionic compound monomer with hydrophic long side chain which namedN,N-dimethyl-N-carboxynonyl-N-methacylolozylethyl ammonium bromide was synthesized bydimethyl aminoethyl methacrylate(DM )and 10-Bromodecanoic acid. At optimum conditions such asreaction temperature 55℃, DM∶10-Bromodecanoic acid=2∶1(molar ratio), reaction time 8h, the yieldof the monomer was 78%. The new monomer was copolymerized with AM to synthesize a comb-likezwitterionic copolymer. The properties of dilute solution of the copolymer was tested and showed thatthe copolymer solution had excellent shearing resistance, salt tolerance and viscoelastic characteristics.