Synthesis And Properties Evaluation Of The Novel Polycarboxyl Sulfonic Acid Copolymer Used As Scale Inhibitor

Copolymer as scale inhibitor is a new type of pollution-free water treatment agent, reach the scale inhibition and dispersion effect by carboxylic, sulfonic acid, amide, hydroxyl, phosphonic acid and other scale feature characteristic group. Acrylic copolymer and other common copolymer as scale inhibitor, the ability of scale inhibitor is poor in the complex conditions, so the research of copolymer as scale inhibitor in the high applicability has widespread application prospect. The main work and results of this thesis:1. Based on the carboxyl group with strong adsorption ability and the amideas electron donor group, the novel monomer with amide and four carboxyl groups N,N’-(2-methylene-1-oxo-1,3-propanediyl)-bis-glycine (MOPBG) was designed and synthesized. The copolymer MOPBG-AM PS and MAA-MOPBG-AMPS were synthesized by free radical polymerization with water as solvent, ammonium persulfate (NH4)2S2O8as initiator, methacrylic acid (MAA),2-acrylamido-2-methyl propane sulfonic acid (AMPS) as monomer. The structure and heat-resistant properties of copolymer were characterized by FTIR1H-NMR and TGA. The scale inhibition rate of copolymer with different polymerization conditions were discussed respectively, the result show that the best polymerization conditions of MOPBG-AMPS:n(MOPBG):n(AMPS)=6:1, reaction temperature is70-75℃, the dosage of initiator to the total mass of monomer8-10%, heat preservation time2-4h; The best polymerization conditions of MAA-MOPBG-AMPS:n(MAA):n(MOPBG): n(AMPS)=3:2:1, reaction temperature75℃, the dosage of initiator to the total mass of monomer8-10%, heat preservation time3h.2. The relation between copolymer dosage, medium temperature, constant temperature time and scale inhibiting rate was studied. The results show that copolymer MOPBG-AMPS and MAA-MOPBG-AMPS as calcium carbonate, barium sulfate, strontium sulfate scale inhibitor, are all suitable for the high temperature and long constant temperature time, the scale inhibition rate is high with low copolymer dosage.3. The morphology of the copolymer MAA-MOPBG-AMPS in aqueous solution were characterized by transmission electron microscope (TEM). The crystal morphology and crystal data of calcium carbonate, barium sulfate, strontium sulfate with copolymer scale inhibitor added or not were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The scale inhibition mechanism of copolymer MAA-MOPBG-AMPS were discussed and summarized.