Synthesis, Solution Property And Application Of Palygorskite/polyacrylamide Hybrid

Recently, inorganic-organic polymer hybrids have caught a great deal of attention from many researchers. The addition of inorganic materials, especially inorganic materials with nano-scale, to organic polymer endows these organic materials many unique physical and chemical properties. So inorganic-organic polymer hybrids have been utilized extensively in structural materials, electronic or optical materials, and membrane materials, but only a few efforts have been made on the syntheses of water-soluble polymers and few study has been made on solution properties of those. In this thesis, a water-soluble hybrid, palygorskite-polyacrylamide was synthesized by polymer-clay method, and this hybrid was used as flocculent in water-treatment.First, a natural mineral, palygorskite(PGS) was acid activated by HC1 solution, and then acid activated palygorskite (APGS) reacted with ethanolamine hydrochloride (EACl), and the modified palygorskite (APGS-EACl) was obtained. Acrylamide was initiated by heterogeneous redox initiator system, composed of reductive agent APGS-EACl together with oxidant Ce4+, and polymerization occurred in the inner surface of nano-scale tunnel of PGS crystal. The palygorskite/polyacrylamide (PGS/PAM) hybrid obtained was characterized by H-NMR, FTIR, viscosimetry and specific conductivity method. It can be interpreted in terms of ion bond structure (PGSeeNH3R) in PGS/PAM hybrid. The influence of dosage of APGS-EACl, polymerization time, and monomer concentration on the of the PGS/PAM hybrid was investigated, and it is also found that the of the hybrid increases with increasing reaction time differing from conventional free-radical polymerization.Dilute solution behavior of water-soluble PGS/PAM hybrid have been investigated by specific conductivity method, viscometry, and size exclusion chromatography (SEC). It was found that the polyelectrolyte behavior and specific conductivity of hybrids in deionized water at low concentration region depend strongly on its degree of ionization, which is firmly connected to the content of APGS-EACl and the intrinsic viscosity. The SEC chromatograms of PGS/PAM hybrid not only display the polyelectrolyte behavior but also reveal unregulated peak. All results indicate that PGS/PAM hybrid is a weak polyelectrolyte, i.e., an ionized hybrid, and probably a star-like ionized hybrid in which the PGS particle acts as a core and the chains of PAM act as arms, according to the SEC chromatograms.Flocculating effect of PGS/PAM hybrid was better than that of pure PAM for both 0.25wt% kaolin suspension and 0.5wt% hematite suspension, respectively. Finally, PGS/PAM hybrid flocculent was also applied in treating real waster water. A new flocculating model for PGS/PAM hybrid flocculent was proposed.