Synthesis And Evaluation Of Hydrophobically Modified Cationic Polyacrylamide

With the diminution of fresh water resource and focusing on the environmental protection, the flocculants played more and more important roles all over the world. Water-soluble cationic polyacrylamide(PAM) can be used as efficient flocculants for many disperse systems such as water treatment, paper-making, mineral processing and other fields.It is desirable to synthesize the hydrophobic flocculants with cationic charges to improve the flocculation performance of domestic flocculants. This paper analyses the development and the existing problems of polymeric flocculant. On this basis, we take into account to use PAM as the molecular backbone, introduce DAC as cation group, C₁₆DMAAC as the hydrophobic group to synthesize hydrophobically modified cationic polyacrylamide with good flocculation performance flocculant. Initiated by multi-initiating system consisting of persulfate and azo-compound, the copolymerization of acrylamide, cationic monomer and hydrophobic monomer has been synthesized through radical copolymerization in water solution..The effects of monomer concentration, pH, dosage of initiator, reaction temperature, hydrophobic monomer concentration and additives were studied. In addition, the polymer molecular structure was confirmed by the infrared absorption spectrum. At last, through the flocculation experiments of using the polymer disposing of urban waste water, the effects of different polymers, cationic and hydrophobic group content,characteristic viscosity,dosage of flocculant and sedimentation time on floccuiation performance were studied.By experiment result, the optimum technical parameters in acrylamide polymerization were confirmed. concentration of monomer: 30 % pH:5temperature of initiator: 15°Cdosage of initiator AM-01 and K₂S₂O₈: 300ppm,35ppm dosage of hydrophobic monomer: 0.25% mol ratio of AM and DAC: 3:1Under the condition, the good flocculant performance of the polymers were available. This kind of polymer can keep the characteristic of the cation macromolecule flocculant, and then can debase the hydrophile function because of the existence of hydrophobic group, enhance the adsorbing ability in suspending grain, simultaneity have the property of hydrophobically associating polymer, further improve the flocculation performance .