Abstract: Porous microspheres encapsulated with rose fragrance were prepared by adsorption of the fragrance on porous polystyrene-divinylbenzene (PSt-DVB) microspheres,which were obtained by two-step swell polymerization with the uniform polystyrene microspheres as seed particles via dispersion polymerization.The surface features of seed particles and porous microspheres were observed by scanning electron microscope (SEM);the particle size,the specific surface area and pore structure were analyzed and characterized by particle size analyzer and Brunauer,Emmett and Teller (BET) method;controlled-release performance was tested by thermal gravimetric analysis (TGA).The results showed that the particle size of the seed particles increases with the increasing of volume fraction of the ethanol.As dosage of the swelling agent,p-dibutyl phthalate (DBP) increases,particle size of the porous microspheres increases and its distribution becomes wider.As the dosage of cross-linking monomer DVB increases,average particle size of the porous microspheres reduces and its distribution becomes narrower.The best single size dispersion was obtained as the porous microspheres were generated with toluene.The porous PSt-DVB microspheres with the diameter of 4 μm were obtained when the ratio of V(DBP)∶m(seed particles) and V(DVB)∶V(St) is 3∶1 and 4∶0,respectively.As a result,the release rate of the fragrance can be slow down and initial decomposition temperature can be raised;and then the controlled release of the fragrance can be realized.

Key words: rose fragrance, dispersion polymerization, seed-swelling, porous microspheres, slow-release