Preparation Of Polymeric Materials And Ultrafine Fibers With Bicontiunuous Porous Structures

Porous polymeric materials could be used in many fields, such as gas absorption, biomedical materials. In this dissertation, two parts were studied: I .Preparation of porous polymeric materials by microemulsion polymerization of methyl methacrylate (MMA). II Preparation of mesoporous ultrafine fiber based on polyacrylonotrile (PAN) using electrospinning fiber.1. Hemi ester of maleic acid (HEC) and a sodium salt of hemi ester of maleic acid (HEC-Na) were synthesized and characterized.2. Microemulsion polymerizations of MMA with HEC12 as the polymerizable surfactant and ethanol as the cosurfactant were studied. It was found that, the introduction of HEC 12 as the polymerizable surfactant was useful for the preparation of polymeric materials with porous structures, but the pores are not bicontinuous and the introduction of HEMA decreased the diameter or the width of the pores.3. Microemulsion polymerizations of MMA with HEC12-Na as the polymerizable surfactant and HEMA as the cosurfactant were studied. It was found that the introduction of HEC12-Na was useful for preparing the polymeric materials with bicontinuous nano-structure and with the increase of HEC12-Na concentration, the porous structure was changed obviously.4. The ultrafine fibers with diameters of about 200-800 nm were prepared by electrospinning, a N, N-dimethylformamide (DMF) solution of a mixture of polyacrylonitrile (PAN) and a copolymer of AN and MMA (Poly(AN-co-MMA)) prepared by free radical polymerization.5. The Poly(AN-co-MMA) component in the ultrafine fibers was selectively removed by rinsing in methylene dichloride (CH₂Cl₂), and the PAN fibers with a mesoporous structure were prepared. The morphology of the pores were partly determined by the weight percent of P(AN-co-MMA). The distribution of the components in the fibers was also discussed.6. The electrospun fibers were oxidized at about 250 ℃, and then carbonized by heating to about 800 ℃. The Poly(AN-co-MMA) component was degraded and the PAN component was carbonized. The carbonized fibers with a mesoporus structure were prepared, whose specific surface area and distribution of pores were also characterized.