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Synthesis and Characterization of High Molecular Weight Polyacrylamide and Cationic Polyacrylamide
Abdollahi Banouei, Zohreh | 2008
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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 39534 (06)
- University: Sharif University of Technology
- Department: Chemical and Petroleum Engineering
- Advisor(s): Frounchi, Masoud; Dadbin, Susan
- Abstract:
- In many industrial processes there is an urgent need for flocculation of suspensions that can’t flocculate easily through the time so flocculants are wildly used in these industries. Polymeric flocculants because of less needed dose are economically used. Polymeric flocculants divided to three categories: nonionic, anionic and cationic those are almost from polyacrylamide group. Studying mechanisms of flocculation, one of the main factors that enhance flocculation is molecular weight of polymer. Hence one of the goals of this work is to improve molecular weights of synthesized polymers as much as possible that is followed by viscometery, NMR, DSC and FTIR studies and ended with jar test. Thermal initiators (KPS, APS) and also redox system (APS- TEMED) were used for reaction initiation. The results show that KPS is better than APS in improving molecular weight and redox system is the best one. Using different mixers it was shown that ultrasonic surpasses mechanical and magnetic mixers in improving molecular weight. Viscometeric studies show that with increasing temperature, intrinsic viscosity decreases until it reaches to theta intrinsic viscosity. With further increase in temperature intrinsic viscosity remains constant. Reduced viscosity vs. polymer concentration curve shows a maximum that disappear with temperature increase. The same behavior was observed with decreasing the molecular weight. The behaviors of polymers were also investigated in water- acetone (methanol) mixtures. The results suggested that acetone (methanol) attached to water molecules those had attached to acrylamide groups of polymers through hydrogen bonding that caused expansion of polymer chain. This idea was confirmed by NMR and DSC studies. NMR studies also show that synthetic copolymer in this work is almost random compare to other works. Rheometric studies show that copolymer is almost elastic compare to cationic homopolymer. Through jar tests it was shown that cationic homopolymer is the best one for flocculation of kaolin suspension and results in 100% kaolin removal.
- Keywords:
- Chemical Synthesis ; Characterization ; High Molecular Weight Polyacrylamide ; Cationic Polyacryamide ; Flocculant
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