Synthesis and application of hyperbranched polyamidoamine particles

Abstract

This thesis deals synthesis and characterization of hyperbranched polyamidoamine (HPAMAM) particles. We attempted the synthesis of various type of HPAMAM particles via inverse suspension polymerization and O/W/O suspension polymerization. These particles can capture the metal ions in aqueous solution and $CO_2$ in flue gas. Firstly, we synthesized silica-HPAMAM hybrid particles. The silica particles have approximately 700 nm diameter, and the surface thickness of HPAMAM is about 20-50 nm. These particles have a better removal ions efficiency of $Cu^{2+}$ ion at the high concentration than Dowex commercial resin. These particles are easy to synthesize, and recyclable with simple acid treatment. Secondly, micro-hydrogel particles fully consisting of HPAMAM were readily synthesized by eco-friendly polyaddition reaction of A2 and B4 type monomers via inverse suspension polymerization. Particles were found to be highly efficient for removing heavy metal ions, such as cadmium, copper, lead, nickel, zinc, and cobalt, from water, $Cu^{2+}$ adsorption capacity recorded high up to 0.17 g/g which is superior to other chelating polymer adsorbents. The superb adsorption capacity comes from good hygroscopic property and high density of amine and amide functional groups without any supporter materials. In addition, easy recycle by controlling pH, successful scale-up, as well as complete removal of metal ions from water throughout the column packed with particles completes a strong candidate of cost-effective adsorbent for water purification. Thirdly, particles and porous HPAMAM particles were obtained by using silica particles via inverse suspension polymerization. The porous HPAMAM particles have about 50 ~ 300 um diameter, and the pore size is about 800 nm diameter. The HPAMAM particles showed many pores that corresponded to the silica particles. As the amount of silica is increase, the number of pore is increased. It was found that the porous HPAMAM particles have a better $Cu^{2+}$ adsorption rate than normal HPAMAM particles. Finally, HPAMAM particles with 30 - 300μm-sized were well synthesized via inverse suspension polymerization, despite the experimental scale was increased. In addition, porous HPAMAM particles were obtained via O/W/O suspension polymerization, these pore size were easily controlled by regulating agitation speed of aqueous phase. The $CO_2$ adsorption was measured by using HPAMAM particles packed within acryl column with a continuous flow of $CO_2$. There was a tendency of deteriorating saturation rate with increasing $CO_2$ concentration and decreasing bed height. As monomer ratio reached the value of 2, the decrease in adsorption capacity was observed, and this was because the diffusion of the dissolved $CO_2$ into the polymer particles became challenging as a result of increased cross-link density of the particles. The $CO_2$ adsorption rate of porous HPAMAM particles was 1.25 times higher than normal HPAMAM particles.