The waterborne particles of bisphenol A epoxy resin were prepared by the phaseinversion technique, and the effects of the concentration of the synthetic polymeric emulslfleron the particles size and structure were dis...The waterborne particles of bisphenol A epoxy resin were prepared by the phaseinversion technique, and the effects of the concentration of the synthetic polymeric emulslfleron the particles size and structure were discussed. At lower concentration of the emulsifier,the bigger molecular sieves alike particles were obtained, on the contrary, the smallerparticles with some aggregation were prepared at higher concentration of the emulslfler. Theformation mechanism of different particle sizes and structure at different concentrations of theemulsifier was proposed. presides, the probable model of the aggregation was also brieflypresented.展开更多
A method for preparing 3D ordered macroporous silicate materials was developed by using the ordered stacking structure of monodispersed polystyrene latex as a template. By using a modified sol\|gel procedure, the orde...A method for preparing 3D ordered macroporous silicate materials was developed by using the ordered stacking structure of monodispersed polystyrene latex as a template. By using a modified sol\|gel procedure, the ordered template was permeated and filled with silicate, and the title porous materials was formed after removing the template by calcination at high temperature. Moreover, the pores were highly ordered throughout all the sample. After observing the morphological profile of the sample before calcination, it was found that silicate existed in two typical morphologies: monodispersed particles in the cavities and interconnected network within the interstice of the template. The transition morphology was rod\|like formed by the condensation of the silicate monodispersed particles. Two aspects concerning with the template effects of the ordered latex film were emphasized: the polymeric spheres may result in orderly packed holes after calcination, and the dielectric interfacial layer surrounding the polymeric spheres may induce the formation of monodispersed silicate spheres with ordered stacking. Both aspects played important roles in the formation of the highly ordered inorganic porous materials by calcination the gel at high temperature.展开更多
Monodispersed polystyrene latexes (100～500 nm) were prepared using seed emulsion polymerization.Hard and ordered polystyrene colloidal crystals were obtained by ambient drying the monodispersed polystyrene dispersion...Monodispersed polystyrene latexes (100～500 nm) were prepared using seed emulsion polymerization.Hard and ordered polystyrene colloidal crystals were obtained by ambient drying the monodispersed polystyrene dispersions.Polystyrene colloidal crystals were chemically modified by controlled sulfonation with sulfuric acid to derive a novel macro ordered hydrogels including ordered hydrogels and core/shell hydrogels,in which sulfuric acid and sulfone groups are responsible for the hydrophilic and crosslinking performances,respectively.The chemical structure and morphologies of the hydrogels were characterized by FT IR.It is shown that at a given concentration of sulfuric acid,the structural features of the samples are controlled by sulfonation time and temperature.The modification starts from the outer layer of polystyrene spheres of the colloidal crystals and increases both in reaction rate and sulfone group amount with temperature.A preliminary mechanism of the sulfonation process to prepare the ordered structures was proposed.展开更多
The effects of emulsifier molecular architecture on phase inversion process including the critical water content at phase inversion point as well as the particle size are investigated. It is found that the water conte...The effects of emulsifier molecular architecture on phase inversion process including the critical water content at phase inversion point as well as the particle size are investigated. It is found that the water content at phase inversion point reaches a maximum when the molar ratio of the hydrophilic component PEG10000 to the hydrophobic component bisphenol A epoxy resin E20 is equal to 1∶1, meanwhile, the particle size reaches a minimum (about 100 nm). From the experimental results, it can be seen that to alter the molecular architecture of the emulsifier is an effective method to control the size of the waterborne particles prepared by phase inversion emulsification technique.展开更多
A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium com...A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.展开更多
Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morp...Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morphology of the titled silica was characterized by transmission electron microscopy and X ray diffraction. The results showed that the pores were worm like and the pore size was about 4 nm. Further nitrogen isothermal absorption experiment indicated that the specific area of the titled material was 391 m 2/g, which was comparable with the reported value 306 m 2/g in literature.展开更多
In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the wa...In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the water evaporation, a skin film with some defects was formed at latex/air interface, water evaporated thereby in a constant rate. During this stage, a drying front advanced from the top film towards the bulk dispersion. Afterwards, most water was lost, and water evaporation rate was less than that of the initial stage. In this case, the whole system became immobile, and another drying front developed from the interior region outside the system. Two distinct boundaries between completely dried region and wet region corresponding to the opposite directions of the second drying front were found if the film peeled from the container bottom surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force due to water evaporation.展开更多
Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase invers...Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase inversion emulsification. The dynamic morphological evolution of water droplets dispersed in bisphenol. A epoxy resin/emulsifier (a multi\|block copolymer) during phase inversion process was investigated with scanning electron microscopy. It is shown that small discrete water droplets are dispersed in the epoxy resin continuous phase at low water content. In this case, the dynamic coalescence among the small water droplets is ignored. With increasing water content, the dynamic coalescence becomes remarkable and larger water drops are formed by the coalescence among the small water droplets. The larger water drops are randomly distributed within the continuous phase. Meanwhile, some necklace like structures with varied length co\|exist with the small water droplets and larger water drops. Incomplete phase inversion is achieved through the coalescence among the larger water drops, and some small water droplets are entrapped therein. In this case, a kind of multi\|hollow sphere is obtained. While, in some local regions, all the nearest small water droplets coalesce simultaneously to be continuous phase to achieve complete phase inversion, and small discrete waterborne particles are obtained. The dynamic coalescence among the small water droplets dispersed in epoxy resin continuous phase could be analyzed in terms of the improved Smoluchowski equation.展开更多
文摘The waterborne particles of bisphenol A epoxy resin were prepared by the phaseinversion technique, and the effects of the concentration of the synthetic polymeric emulslfleron the particles size and structure were discussed. At lower concentration of the emulsifier,the bigger molecular sieves alike particles were obtained, on the contrary, the smallerparticles with some aggregation were prepared at higher concentration of the emulslfler. Theformation mechanism of different particle sizes and structure at different concentrations of theemulsifier was proposed. presides, the probable model of the aggregation was also brieflypresented.
文摘A method for preparing 3D ordered macroporous silicate materials was developed by using the ordered stacking structure of monodispersed polystyrene latex as a template. By using a modified sol\|gel procedure, the ordered template was permeated and filled with silicate, and the title porous materials was formed after removing the template by calcination at high temperature. Moreover, the pores were highly ordered throughout all the sample. After observing the morphological profile of the sample before calcination, it was found that silicate existed in two typical morphologies: monodispersed particles in the cavities and interconnected network within the interstice of the template. The transition morphology was rod\|like formed by the condensation of the silicate monodispersed particles. Two aspects concerning with the template effects of the ordered latex film were emphasized: the polymeric spheres may result in orderly packed holes after calcination, and the dielectric interfacial layer surrounding the polymeric spheres may induce the formation of monodispersed silicate spheres with ordered stacking. Both aspects played important roles in the formation of the highly ordered inorganic porous materials by calcination the gel at high temperature.
文摘Monodispersed polystyrene latexes (100～500 nm) were prepared using seed emulsion polymerization.Hard and ordered polystyrene colloidal crystals were obtained by ambient drying the monodispersed polystyrene dispersions.Polystyrene colloidal crystals were chemically modified by controlled sulfonation with sulfuric acid to derive a novel macro ordered hydrogels including ordered hydrogels and core/shell hydrogels,in which sulfuric acid and sulfone groups are responsible for the hydrophilic and crosslinking performances,respectively.The chemical structure and morphologies of the hydrogels were characterized by FT IR.It is shown that at a given concentration of sulfuric acid,the structural features of the samples are controlled by sulfonation time and temperature.The modification starts from the outer layer of polystyrene spheres of the colloidal crystals and increases both in reaction rate and sulfone group amount with temperature.A preliminary mechanism of the sulfonation process to prepare the ordered structures was proposed.
文摘The effects of emulsifier molecular architecture on phase inversion process including the critical water content at phase inversion point as well as the particle size are investigated. It is found that the water content at phase inversion point reaches a maximum when the molar ratio of the hydrophilic component PEG10000 to the hydrophobic component bisphenol A epoxy resin E20 is equal to 1∶1, meanwhile, the particle size reaches a minimum (about 100 nm). From the experimental results, it can be seen that to alter the molecular architecture of the emulsifier is an effective method to control the size of the waterborne particles prepared by phase inversion emulsification technique.
文摘A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.
文摘Surfactant template synthesis of mesoporous silica monolith was carried out via modified fast sol gel process. It was easy to obtain crack free silica monolith due to low volume shrinkage during the gelation. The morphology of the titled silica was characterized by transmission electron microscopy and X ray diffraction. The results showed that the pores were worm like and the pore size was about 4 nm. Further nitrogen isothermal absorption experiment indicated that the specific area of the titled material was 391 m 2/g, which was comparable with the reported value 306 m 2/g in literature.
文摘In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the water evaporation, a skin film with some defects was formed at latex/air interface, water evaporated thereby in a constant rate. During this stage, a drying front advanced from the top film towards the bulk dispersion. Afterwards, most water was lost, and water evaporation rate was less than that of the initial stage. In this case, the whole system became immobile, and another drying front developed from the interior region outside the system. Two distinct boundaries between completely dried region and wet region corresponding to the opposite directions of the second drying front were found if the film peeled from the container bottom surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force due to water evaporation.
文摘Phase inversion emulsification technique is an effective physical method to prepare waterborne dispersions of polymeric resins. In this study, a multi\|hollow epoxy resin sphere was obtained by incomplete phase inversion emulsification. The dynamic morphological evolution of water droplets dispersed in bisphenol. A epoxy resin/emulsifier (a multi\|block copolymer) during phase inversion process was investigated with scanning electron microscopy. It is shown that small discrete water droplets are dispersed in the epoxy resin continuous phase at low water content. In this case, the dynamic coalescence among the small water droplets is ignored. With increasing water content, the dynamic coalescence becomes remarkable and larger water drops are formed by the coalescence among the small water droplets. The larger water drops are randomly distributed within the continuous phase. Meanwhile, some necklace like structures with varied length co\|exist with the small water droplets and larger water drops. Incomplete phase inversion is achieved through the coalescence among the larger water drops, and some small water droplets are entrapped therein. In this case, a kind of multi\|hollow sphere is obtained. While, in some local regions, all the nearest small water droplets coalesce simultaneously to be continuous phase to achieve complete phase inversion, and small discrete waterborne particles are obtained. The dynamic coalescence among the small water droplets dispersed in epoxy resin continuous phase could be analyzed in terms of the improved Smoluchowski equation.
