| 초록 |
It was an object of the present proceeding to produce condensation polymers in theform of microspheres by one-step process which is capable of alternating the existingprocess which requires very high temperature and vacuum to allow the removal of thecondensate molecule from the polymer melt. The removal of the condensate molecule isfacilitated by the ability of supercritical CO2 to act as a plasticizing agent for thepolymer phase. In this approach, phenolic/furfural/heptyl alcohol mixtures were dispersedin supercritical CO2 varied with temperature and pressure of the system. The solubilityof alcohols in supercritical CO2 varied with temperature and pressure of the system.This behavior of supercritical CO2 enables the synthesis of organic aerogel microspheresby one-step process. When the dispersion phase was insoluble in supercritical CO2, itwas emulsified in it by means of a CO2-soluble stabilizer with high temperature andlow pressure, phase separation occurred and led to the formation of P/F gelmicrospheres. At the inversion of process condition, alcohol in the P/F gel microsphereswas exchanged with supercritical CO2 continuously, which was supercritically dried toobtain organic aerogel microspheres. The reactants were exchanged into supercriticalCO2 in 40 ℃, after which it was supercritically dried. Poly(dimethylsiloxane) (PDMS)was used as the stabilizer in this system. The spherical polymer particles were isolatedby simply venting the supercritical CO2 from the reaction mixture. Scanning electronmicroscopy showed that the product consisted of spheres in the micrometer size range.
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