Fabrication Of Macroporous Polystyrene By Templating Against Copolymer Microsphere

Porous materials have been widely used as catalytic surfaces and supports, separation and adsorbent media, biomaterials, chromatographic materials, and thermal, acoustic, and electrical insulators because they features high ratio of surface to volume, adsorbent capacity and special properties.Templating synthesis is a convenient and versatile method for generating porous materials. It is also a cost-effective and high-throughput procedure that allows the complex topology present on the surface of a template to be duplicated in a single step. In this technique, the template simply serves as a scaffold around which other kinds of materials are synthesized. Fabrication based on this approach is remarkable for its simplicity, and for its fidelity in transferring the structure from the template to the replica. The size of the pores and the periodicity of the porous structures can be precisely controlled and readily tuned by changing the size of the template microspheres.Uniformly sized, three dimensionally interconnected porous PS materials have been produced by templating against the submicrometer spheres with plenty remained maleic anhydride (MAn) onto their surfaces.Since MAn has very high alternating copolymerization reactivity with styrene (ST), by templating this kind of microspoheres many functional groups can be introduced onto the pore-surfaces of porous materials in situ. In the studies, we found that not only the size of pores but also the amount of functional groups onto the pore-surface can be controlled by adjusting the size of microspheres or changing the monomer feed ratio for the microspheres. The production of template has been described in the Patent. The template of maleic anhydride/ vinyl acetate copolymer microspheres is uniform and the controllable size ranges from 130 to 600nm. During the synthesis of the templates, we found that as-synthesized latex produced by a free stabilizer dispersion polymerization can give out copolymer necklaces with micrometer scale by evaporating solvent. And the necklace structures can spread two dimensionally and three dimensionally. So, we had fabricated mcirostructured materials by templating the class of loosely packed template. The materials with pores in the specific region can increase the surface area in the specific region without influencing the mechanical properties.This paper is composed of two parts. The first is fabrication of material with pores in the specific region which studied the effects of several materials as well as template latex density on packing of uniform microspheres and the effects of different removing solvents, the ratio of cross-linker and initiator in synthetic system, the time of removing template in solvent on pore morphology. The second elaborates the production of porous PS monoliths. In this part, the effects of template content in the system of template/monomers, size of template, the different removing solvents, the time of removing template on the morphology of pores and at last, the effect of monomers feed ratio of synthesis of template on the anhydride groups density onto pore-surface had been investigated. The products were characterized by FTIR, SEM, titration method and IBAS 1/2...