常用工程英语词汇.doc

PREPARATION AND PERFORMANCE OF FRAGRANT POWDERS
Abstract
Fragrant powders, which have unique aroma, were made up of the anic carrier materials and flavors. Microcapsules, porous biomaterials and porous polymer microspheres were used mon carrier materials. The internal flavors were released easily without exogenic action on porous microspheres, which has big specific surface area and adsorption capacity. The porous microspheres, which were physically and chemically stable, could be modified with more function group on the surface. So it is widely used in chemical industry, daily cosmetics and so on.
The paper posed of three parts. In the first part, under the alcohol/water ratio of 80/20, small particle size monodisperse polystyrene microspheres were synthesized by dispersion polymerization. Porous polystyrene-divinylbenzene(PSt-DVB)microspheres were obtained by two-step swell polymerization with the above microspheres as seed particles. The effects of the content of swelling agent, the crosslinking monomers and the types of porogen on the porous microspheres particle size, morphology and pore structure were investigated. The porous
PSt-DVB microspheres with the uniform pore structure, the specific surface area of 158m2/g and
the pore volume of were synthesized when the ratio of the volume of butyl phthalate (DBP)/m(seed particles)was 3/1,the volume of divinyl benzene (DVB) and toluene used as porogen were both 4ml.
In the second part, the fragrant powders were prepared by static adsorption of rose essence on the porous microspheres. The adsorption principle was proved to be physical adsorption by infrared spectroscopy. The process parameters effected the adsorption quantity, such as time, temperature, initial volume fraction of rose essence, different porous microspheres, were also discussed in detail. Fragrant powders with large adsorption amount were prepared when the
adsorption temperature was 40 ℃, adsorption time was 2h and the initial volume