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
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
The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown t...The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.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
For the concentrated dispersions of epoxy resin prepared by phase inversion emulsification technique, the effects of solid content and temperature on the rheological behavior are studied. It is found that there exists...For the concentrated dispersions of epoxy resin prepared by phase inversion emulsification technique, the effects of solid content and temperature on the rheological behavior are studied. It is found that there exists reversible structural transition in concentrated dispersions subjected to shearing. The viscosity oscillation correlated with high viscoelasticity at lower stress is remarkable in highly concentrated dispersions. There exists storage modules overshot at higher stress during the dynamic stress time ramp test. This could provide some information on dynamics of structure changes during shear action. Besides, the effects of solid content and temperature on the relationship between tangent delta and frequency are essentially different.展开更多
Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dis...Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dispersant. Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black （CB） particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it Increased by ultrasonic with the increase of CMC viscosity. Uitrasonk is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size lbviously decreased with itcreasing ultrasonic time and arrived at about 160 nm for 60min.In addition,oxidation with 2 mol/L of H2O2 and 0.2wt% of CMC300 reduced CB particle size to 160nm at 90℃ for 2.5h.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.
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 supported by the National Natural Science Foundation of China (Grant No. 29774038), and 973 project "Fundamental study on enhanced oil recovery" of the Ministry of China Science and Technology.
文摘The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.
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.
文摘For the concentrated dispersions of epoxy resin prepared by phase inversion emulsification technique, the effects of solid content and temperature on the rheological behavior are studied. It is found that there exists reversible structural transition in concentrated dispersions subjected to shearing. The viscosity oscillation correlated with high viscoelasticity at lower stress is remarkable in highly concentrated dispersions. There exists storage modules overshot at higher stress during the dynamic stress time ramp test. This could provide some information on dynamics of structure changes during shear action. Besides, the effects of solid content and temperature on the relationship between tangent delta and frequency are essentially different.
基金Supported by National Natural Science Foundation of China( No.50173012) and863Hi-tech Research and Development Program ofChina (2002AA327120)
文摘Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dispersant. Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black （CB） particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it Increased by ultrasonic with the increase of CMC viscosity. Uitrasonk is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size lbviously decreased with itcreasing ultrasonic time and arrived at about 160 nm for 60min.In addition,oxidation with 2 mol/L of H2O2 and 0.2wt% of CMC300 reduced CB particle size to 160nm at 90℃ for 2.5h.
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).
