PHOTOPOLYMERIZATION OF POLY(ETHYLENE GLYCOL) DIACRYLATE IN SUPERCRITICAL CARBON DIOXIDE

The process of photopolymerization of polyethylene glycol diacrylate in supercritical carbon dioxide system was explored. Supercritical carbon dioxide was obtained in a high pressure chamber by adding carbon dioxide into the chamber and adjusting the temperature and pressure befittingly. Then carbon dioxide, and solution of reactive monomer and photo initiator were sprayed simultaneously into the high pressure chamber to form mist of the reactants interacting with carbon dioxide, and the further uniform dispersion system of reactant in supercritical carbon dioxide could be got by anti solvent effect. The results showed that the photopolymerization of active monomer in supercritical carbon dioxide performed successfully under irradiation of UV light resource as prospected and crosslinked polymer microparticles were produced. Furthermore, the relationship of the kind of solvent the quantity of the reactants with the distribution properties of the microparticle size was investigated. It could be seen that the distribution of the microparticle size broadened with the decreasing of the solubility of the reactants in supercritical carbon dioxide which was caused by the larger polarity of the solvent and the poor solubility of the solvent in supercritical carbon dioxide. The results also showed that the distribution of the microparticle size increased with the increasing of quantity of the reactants.