| Porous polymer materials have many certain advantages, such as light weight,large specific surface, good permeability, high adsorption capacity, etc. They havepotential applications in aviation, aerospace, environmental protection, medicine,chemicals, etc. Hollow polymer microspheres and ordered porous polymermonolithic materials are representative. However, hollow polymer microspheresexisting problems of poor uniformity and easy to collapse, porous polymermonolithic materials has bad order state. This review focuses primarily on thesynthesis of hollow crosslinked polystyrene microspheres and epoxy groupfunctionalized hollow crosslinked polystyrene microspheres with monodispersesizes and stable structure and the fabrication of ordered porous expoxy monolithicmaterials with a uniform pore distribution and stable structure. Moreover, theiradsorption ability for toluene were initially explored and compared. And theirapplications in wastewater treatment were evaluated.1. Preparation of hollow crosslinked polymer microspheres. Polystyrenemicrospheres were first prepared by dispersion polymerization and werecharacterized by laser particle analyzer and SEM. The optimum formula wasdetermined through continuous experiments. Nearly monodispersed polystyrenecore-shell microspheres were subsequently prepared by using polystyrenemicrospheres as temples. The effects of the amount, the time and the means ofadding crosslinking agent (divinlbenzene) were studied. The results indicated thatthe optimal experimental scheme was to add30wt%divinlbenzene into the reactionsystem when styrene was polymerized for2.5hours. Hollow microspheres with acrosslinked shell were finally obtained, after selective removal of the uncrosslinkedcore form the core-shell polymer microspheres. After being extensivelycharacterized by laser particle analyzer, SEM, FTIR, BET, the polystyrenemicrospheres were proved to be hollow. Before and after removing the core, thepolydispersity index of particle size was0.037and0.034respectively, the specificsurface area was2.591m2/g and180.786m2/g respectively, the maximum amountsof nitrogen adsorption was3.583cm3/g and216.967cm3/g respectively, the amounts of methylbenzene adsorption was0.091g/g and1.359g/g at30℃respectively.In order to decrease mass transfer resistance during adsorption process,glycidyl methacrylate was chosen as the functional monomer to fabricate thefunctionalized hollow microspheres because of its polarity group, which also pavethe way for further functionalization. The effects of the amount, the time of addingfunctional monomer and crosslinking agent on the monodispersion of microspheresand the structural stability were studied. The testing results indicated that theoptimal experimental scheme was to add30wt%divinlbenzene into the reactionsystem when styrene and glycidyl methacrylate were copolymerized for2.0hours.Before and after removing the core, their degree of sphericity, monodispersity andstructural stability are ideal. Before and after removing the core, the polydispersityindex of particle size were0.037, the specific surface area was3.126m2/g and220.336cm3/g respectively, the maximum amounts of nitrogen adsorption was5.513m2/g and264.874cm3/g respectively, the amounts of methylbenzeneadsorption was0.138g/g and1.653g/g at30℃respectively.2. Preparation of ordered porous polymer monolithic materials. In order tofabricate ordered porous monolithic materials, firstly, the PS-b-PLLA blockcopolymer self-assemble into the helical structure. Then, the ordered helical porousPS was prepared via selective removal of PLLA, which was used as temples tofabricate epoxy resin monolithic materials. After being extensively characterized bySEM, TEM, SAXS and BET, the products with good adsorption were proved to behelical porous structure. However, the orderliness of the pore structure needs to beimproved. The specific surface area was743.773m2/g, the maximum amount ofnitrogen adsorption was767.982cm3/g, and the amount of methylbenzeneadsorption was4.782g/g at30℃. Compared with the monodisperse hollowcrosslinked polymer microsphere, ordered porous epoxy resin has larger specificsurface area and better adsorption performance. |
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