Preparation, Modification Of Polystyrene Porous Microspheres And Its Application In Mixed Mode Liquid Chromatography

Polymer porous microspheres have the advantages of being porous and highly crosslinked compared to ordinary polymer microspheres.The porous structure results in a large surface area,a much smaller osmotic pressure,and high crosslinking degree which lead to more stable mechanical properties.So they have a wide range of applications in chromatography and so on.As a key component of liquid chromatography,the performance of the column depends on the performance of the column packing.The modification of the porous microspheres to improve the chromatographic separation performance has been paid attention by more and more scientific researchers.In this paper,based on the advantages of the two-step swelling method of synthesis of porous polymer microspheres,the effects of various factors on the surface morphology of porous microspheres were investigated.And we modified the porous microspheres,examined its performances in terms of chromatography.The specific work is as follows:1.The monodisperse polystyrene porous microspheres with particle size of 5 ?m were successfully synthesized by the two-step swelling method.The effects of porogen ratio,swelling temperature and cross-linking agent on the morphology of porous polymer microspheres were investigated.When the ratio of dibutyl phthalate and toluene is 1:3,the specific surface area of polystyrene porous microspheres is the largest.When the swelling temperature is 25 ?,the surface of the polystyrene porous microspheres is the most rough.When the crosslinking agent is ethylene glycol dimethacrylate,the structure of polystyrene porous microspheres is relatively loose.Comparing the specific area of the porous microspheres,the P(S-DVB)-4 was the largest which was 562 m~2/g.2.The polymer porous microspheres were modified by diazo resin,and several chromatographic separation experiments were carried out with modified microspheres as column packing.By using the principle of photo-crosslinking,the functionalized modification of the polymer microspheres was achieved by replacing the toxic silanization reagent with water-soluble photographic polymer diazo resin.The microspheres were first sulfonated,and the diazoresin was grafted by the sulfonic acid group.Then finally irradiated with ultraviolet light to convert the electrostatic interaction into covalent interaction.The chromatographic separation was carried out with the modified microspheres,a mixture of four benzene homologues,four organic acids and C60,C70 were chromatographed,and compared with the pre-modified polymer microspheres and the commercial column of C18.In this paper,we synthesized the porous polystyrene microspheres and the effects of polystyrene porous microspheres on the surface morphology were investigated,which was of great significance to realize the control of pore size distribution and specific surface area.The subsequent modification of the porous microspheres combines the advantages of physical adsorption and chemical bonding methods,which is an efficient,stable and green method for the functionalization of polymer microspheres by light crosslinking.Chromatographic separation of the mixture of four benzene homologues,four organic acids and C60,C70 also indicated that it had a significant improvement in chromatographic performance.