POLY 507 |
| The core-shell PNIPAM/CMS microgels were obtained directly from one step seed polymerization of N-isopropylacrylamide(NIPAM) and N,N-methylenebisacrylamide from water-soluble biopolymers containing carboxymethyl groups in supercritical carbon dioxide within 6 h. The effect of initial concentration of initiator, cross-linker, and carboxymethyl starch (CMS) dose as well as reaction pressures on the yield and morphology of the resulting polymer were investigated. It was found that CMS and cross-linker worked effectively as surfactant to some extent. At CMS/NIPAM weight ratio 1.3/10, relatively uniform microspheres were obtained with diameters in 50 nm. The particles formed from higher cross-linker agent (0.025g) samples were significantly less agglomerated than those formed from lower cross-linker agent (0.008g) samples. The polymer products distribute dominates changing from top to bottom of the autoclave with pressure increased from 165 to 330 bar. The morphology and structure of the products were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). |
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Nanoparticles and Microparticles: Synthesis and Applications
6:00 PM-8:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Polymer Chemistry |