In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical mode...In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical model is proposed which can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion. In the presence of a latent curing catalyst, PIE can give a crosslinkable epoxy resin waterborne dispersion. The dispersions can form cured transparent coatings with some unique properties such as UV shielding. They are promising in functional coatings, waterborne resin matrices for composites, and sizing for high performance fibers.展开更多
Based on the insight into the mechanism of phase inversion emulsification in the presence of curing agents, a new method called surfactant free phase inversion emulsification was proposed to prepare epoxy resin waterb...Based on the insight into the mechanism of phase inversion emulsification in the presence of curing agents, a new method called surfactant free phase inversion emulsification was proposed to prepare epoxy resin waterborne dispersions. The waterborne particles are in sub micron range with narrow size distribution. Transparent cured films could be formed from the dispersions even at ambient temperature. The stability of the dispersions could be enhanced by post polymerization at a high temperature for some time. The knowledge about the phase inversion and the stability of the waterborne dispersions might provide a new way to enhance oil recovery.展开更多
This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The ke...This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The key is to add the curing agent in the vicinity of the phase inversion point at low temperature so as to control the emulsifier capability of the pre\|curing oligomers at a low level,which ensures the achievement of incomplete phase inversion emulsification.Scanning electron micrographs of the spheres reveal that the particles size is mainly in the range of 1～10 μm with sub\|micron cavities within the spheres.DSC is used to measure the curing behavior of the spheres.Two broad exothermic peaks around 120 and 162℃ are found in the as\|prepared particles,while the first peak shifts to higher temperature 135℃ and the onset temperature exceeds 100℃ in the thermally treated sample at 95℃ for 1 5?h.This indicates that the initial step curing process under the post\|treatment conditions is nearly completed.After further treated at high temperature for example 200℃,a glass transition temperature about 130℃ is found,and the two peaks disappear due to a full achievement of the curing process.Extraction results show that after treated at 95℃ for 1 5?h in water,the micro\|sized spheres become insoluble.It is concluded that the entitled waterborne microspheres are crosslinkable and multiporous.A preliminary result demonstrates a potential application of the entitled multi\|hollow spheres as opacifiers due to their intensive light scattering within the hollows.展开更多
The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne...The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.展开更多
Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples posses...Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.展开更多
Phase inversion emulsification technique is a recently developed method to achieve waterborne dispersions of polymer resin. It is found that the electrical and rheological properties of the system experience abrupt ch...Phase inversion emulsification technique is a recently developed method to achieve waterborne dispersions of polymer resin. It is found that the electrical and rheological properties of the system experience abrupt changes in the vicinity of the phase inversion point (PIP). Before PIP, the system is a Newtonian fluid. At PIP, the continuous phase transforms from polymer resin to water phase with the result that the electrical resistance of the system drops abruptly. Meanwhile, the system at PIP exhibits high viscoelasticity originated from the formation of a physical gel alike structure among the waterborne particles. Besides, the morphology evolution is observed by Scanning Electron Microscopy (SEM).展开更多
基金This project is supported by NSF of China(Nos. 20104008 and 29774038)State Key Laboratory of Polymer Physics and Chemistry.
文摘In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical model is proposed which can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion. In the presence of a latent curing catalyst, PIE can give a crosslinkable epoxy resin waterborne dispersion. The dispersions can form cured transparent coatings with some unique properties such as UV shielding. They are promising in functional coatings, waterborne resin matrices for composites, and sizing for high performance fibers.
文摘Based on the insight into the mechanism of phase inversion emulsification in the presence of curing agents, a new method called surfactant free phase inversion emulsification was proposed to prepare epoxy resin waterborne dispersions. The waterborne particles are in sub micron range with narrow size distribution. Transparent cured films could be formed from the dispersions even at ambient temperature. The stability of the dispersions could be enhanced by post polymerization at a high temperature for some time. The knowledge about the phase inversion and the stability of the waterborne dispersions might provide a new way to enhance oil recovery.
文摘This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The key is to add the curing agent in the vicinity of the phase inversion point at low temperature so as to control the emulsifier capability of the pre\|curing oligomers at a low level,which ensures the achievement of incomplete phase inversion emulsification.Scanning electron micrographs of the spheres reveal that the particles size is mainly in the range of 1～10 μm with sub\|micron cavities within the spheres.DSC is used to measure the curing behavior of the spheres.Two broad exothermic peaks around 120 and 162℃ are found in the as\|prepared particles,while the first peak shifts to higher temperature 135℃ and the onset temperature exceeds 100℃ in the thermally treated sample at 95℃ for 1 5?h.This indicates that the initial step curing process under the post\|treatment conditions is nearly completed.After further treated at high temperature for example 200℃,a glass transition temperature about 130℃ is found,and the two peaks disappear due to a full achievement of the curing process.Extraction results show that after treated at 95℃ for 1 5?h in water,the micro\|sized spheres become insoluble.It is concluded that the entitled waterborne microspheres are crosslinkable and multiporous.A preliminary result demonstrates a potential application of the entitled multi\|hollow spheres as opacifiers due to their intensive light scattering within the hollows.
基金This work was supported by the National Key Project for Fundamental Research, "Macromolecular Condensed State" of Ministry of Science and Technology of China and National Natural Science Foundation of China 29774038.
文摘The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.
基金This work was financially supported by the National Natural Science Foundation of China(No.20104008).
文摘Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.
基金This project is supported by Polymer PhysicsLaboratory, Institute of Chemistry the Chinese Academy of Sciences
文摘Phase inversion emulsification technique is a recently developed method to achieve waterborne dispersions of polymer resin. It is found that the electrical and rheological properties of the system experience abrupt changes in the vicinity of the phase inversion point (PIP). Before PIP, the system is a Newtonian fluid. At PIP, the continuous phase transforms from polymer resin to water phase with the result that the electrical resistance of the system drops abruptly. Meanwhile, the system at PIP exhibits high viscoelasticity originated from the formation of a physical gel alike structure among the waterborne particles. Besides, the morphology evolution is observed by Scanning Electron Microscopy (SEM).
