| 초록 |
It was an object of the present proceeding to produce condensation polymers in the form of microspheres by new process which is capable of alternating the existing process which requires very high temperature and vacuum to allow the removal of the condensate molecule from the polymer melt. The removal of the condensate molecule is facilitated by the ability of supercritical CO2 to act as a plasticizing agent for the polymer phase. In this approach, phenolic/furfural/alcohol mixtures were dispersed in supercritical CO2. The solubility of alcohol in supercritical CO2 varied with temperature and pressure of the system. As process condition varied, P/F gel particles were successfully prepared. The reactants were heated to 80℃ to form the gel particles. The alcohol in the P/F gel particles was exchanged with supercritical CO2 in 40℃ continuously, after which they were supercritically dried. The overall experimental proceeded by one-step process. P/F organic aerogel particles prepared using the tri-block copolymer as stabilizer have average diameter in the range of 50-100 nm. On the other hand, the particles prepared using the poly(dimethylsiloxane) (PDMS) have average diameter in the range of 1-6 mm. The spherical polymer particles were isolated by simply venting the supercritical CO2 from the reaction mixture. The particle size of P/F aerogel depends on different solid contents. The pore size distribution and surface area were varied with Phenolic/Catalyst (P/C) ratio. The morphology of P/F aerogel was observed by SEM and TEM, and the evaluation of surface area and pore size distribution was done by BET. |
