The Experts below are selected from a list of 5343 Experts worldwide ranked by ideXlab platform
Zhen Tong - One of the best experts on this subject based on the ideXlab platform.
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facile fabrication of polystyrene halloysite nanotube microspheres with core shell structure via pickering Suspension Polymerization
Polymer Bulletin, 2012Co-Authors: Hao Liu, Chaoyang Wang, Shengwen Zou, Zengjiang Wei, Zhen TongAbstract:In this article, a facile method for fabrication of core–shell nanocomposite microspheres with polystyrene (PS) as the core and halloysite nanotubes (HNTs) as the shell via Pickering Suspension Polymerization was introduced. Stable Pickering emulsions of styrene in water were prepared using HNTs without any modification as a particulate emulsifier. The size of the Pickering emulsions varied from 195.7 to 26.7 μm with the water phase volume fraction increasing from 33.3 to 90.9 %. The resulting Pickering emulsions with the water phase volume fraction of above 66.7 % were easily polymerized in situ at 70 °C without stirring. HNTs played an important role during Polymerization and effectively acted as building blocks for creating organic–inorganic nanocomposite microspheres after Polymerization. The sizes of PS/HNTs microspheres were roughly in accord with that of the corresponding emulsion droplets before Polymerization. The effect of the water phase volume fraction on the stability of Pickering emulsions and the morphologies of nanocomposite microspheres was investigated by optical microscopy, confocal laser scanning microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and so on.
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dual nanocomposite multihollow polymer microspheres prepared by Suspension Polymerization based on a multiple pickering emulsion
Polymer Chemistry, 2010Co-Authors: Quanxing Gao, Chaoyang Wang, Hongxia Liu, Yunhua Chen, Zhen TongAbstract:A solid-stabilized multiple w/o/w or o/w/o emulsion was prepared in a two-step process. Various nanocomposite polymer microspheres with multihollow armored closed pores were fabricated easily by Suspension Polymerization of the multiple Pickering stabilized emulsions.
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facile fabrication of nanocomposite microspheres with polymer cores and magnetic shells by pickering Suspension Polymerization
Reactive & Functional Polymers, 2009Co-Authors: Chaoyang Wang, Yunhua Chen, Chengjin Zhang, Zhen TongAbstract:Abstract Pickering Suspension Polymerization was used to prepare magnetic polymer microspheres that have polymer cores enveloped by shells of magnetic nanoparticles. Styrene was emulsified in an aqueous dispersion of Fe3O4 nanoparticles using a high shear. The resultant Pickering oil-in-water (o/w) emulsion stabilized solely by magnetic nanoparticles was easily polymerized at 70 °C without stirring. Fe3O4 nanoparticles act as effective stabilizers during Polymerization and as building blocks for creating the organic–inorganic hybrid nanocomposite after Polymerization. The fabricated magnetic nanocomposites were characterized by FTIR, XRD, TGA, DSC, GPC, XPS and SEM. The structures of the polymer core and the nanoparticle shell were analyzed. We investigated the effects on the products of the weight of Fe3O4 nanoparticles used to stabilize the original Pickering emulsions. Pickering Suspension Polymerization provides a new route for the synthesis of a variety of hybrid nanocomposite microspheres with supracolloidal structures.
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Suspension Polymerization based on inverse pickering emulsion droplets for thermo sensitive hybrid microcapsules with tunable supracolloidal structures
Polymer, 2009Co-Authors: Quanxing Gao, Chaoyang Wang, Hongxia Liu, Chenhong Wang, Xinxing Liu, Zhen TongAbstract:Polymerization using Pickering emulsion droplets as reaction vessels is being developed to become a powerful tool for fabrication of hybrid polymer particles with supracolloidal structures. In this paper, two kinds of thermo-sensitive hybrid poly(N-isopropylacrylamide) (PNIPAm) microcapsules with supracolloidal structures were successfully prepared from Suspension Polymerization stabilized by SiO2 nanoparticles based on inverse Pickering emulsion droplets. SiO2 nanoparticles could self-assemble at liquid–liquid interfaces to form stable water-in-oil inverse Pickering emulsion. NIPAm monomers dissolving in suspended aqueous droplets were subsequently polymerized at different temperatures. The hollow microcapsules with SiO2/PNIPAm nanocomposite shells were obtained when the reaction temperature was above the lower critical solution temperature (LCST) of PNIPAm. While the core–shell microcapsules with SiO2 nanoparticles' shells and PNIPAm gel cores were produced when the Polymerization was conducted at the temperature lower than LCST using UV light radiation. The supracolloidal structures with different cores could be tuned by simply changing reaction temperature, which was confirmed by confocal laser scanning microscopy and scanning electron microscopy. The interesting properties of both microcapsules were their ability of reversibly swelling during drying/wetting cycles and responsive to temperature stimulus. Such functional microcapsules may find applications in double control release system due to the presence of the supracolloidal structures and thermo-sensitivity.
Han Mo Jeong - One of the best experts on this subject based on the ideXlab platform.
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graphene functionalized with poly vinyl alcohol as a pickering stabilizer for Suspension Polymerization of poly methyl methacrylate
Journal of Colloid and Interface Science, 2016Co-Authors: Gansukh Erdenedelger, Han Mo JeongAbstract:Abstract Two types of thermally reduced graphenes (TRGs) having different lateral sizes were non-covalently modified with poly(vinyl alcohol) to endow water-dispersibility. The modified TRGs were examined as Pickering stabilizers for the Suspension Polymerization of methyl methacrylate (MMA). They were effective graphene-based Pickering stabilizers for the system with almost all of the polymerized composite microparticles having a regular spherical shape. The particle size of the composite microparticles was tunable by the size or the amount of modified TRG used as stabilizer. The almost perfect core-shell structure of the composite microparticles effectively enhanced the thermal stability of the core PMMA. In addition, when the core-shell microparticles were compression molded into a monolith, the obtained composite exhibited an ultra-low percolation threshold of electrical conductivity of around 0.04 vol%.
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water dispersible graphene designed as a pickering stabilizer for the Suspension Polymerization of poly methyl methacrylate graphene core shell microsphere exhibiting ultra low percolation threshold of electrical conductivity
Polymer, 2014Co-Authors: Gansukh Erdenedelger, Han Mo JeongAbstract:Abstract The microsphere of poly(methyl methacrylate) (PMMA)/graphene composite, having a core–shell structure, is effectively prepared by Pickering Suspension Polymerization using a water-dispersible sulfonated graphene alone as a Pickering stabilizer. This is the first case where a graphene is designed as a Pickering stabilizer for Suspension Polymerization. The sulfonated graphene is prepared using a novel covalent modification method that utilizes the epoxide groups on graphene, which are the inherent defects of thermally reduced graphene, to react with potassium 2-aminoethanesulfonate, without any additional damage to the intrinsic conjugated sp 2 carbon network of the graphene. The size of the microsphere is tunable by the amount of graphene from several tens to several hundreds of micrometers. The thermal stability of PMMA at the core is substantially improved by the thermally stable graphene shell enclosing it. The compression molded composite of the microspheres displays an excellent electrical conductivity of 15.7 S m −1 at a graphene content of 5.33 phr (2.78 vol.%) and an ultra-low percolation threshold of 0.04 phr (0.02 vol.%), which is the lowest value ever reported for polymer/graphene composites, because the graphene shells form a well-defined, three-dimensional conductive graphene network throughout the composite.
Chaoyang Wang - One of the best experts on this subject based on the ideXlab platform.
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facile fabrication of polystyrene halloysite nanotube microspheres with core shell structure via pickering Suspension Polymerization
Polymer Bulletin, 2012Co-Authors: Hao Liu, Chaoyang Wang, Shengwen Zou, Zengjiang Wei, Zhen TongAbstract:In this article, a facile method for fabrication of core–shell nanocomposite microspheres with polystyrene (PS) as the core and halloysite nanotubes (HNTs) as the shell via Pickering Suspension Polymerization was introduced. Stable Pickering emulsions of styrene in water were prepared using HNTs without any modification as a particulate emulsifier. The size of the Pickering emulsions varied from 195.7 to 26.7 μm with the water phase volume fraction increasing from 33.3 to 90.9 %. The resulting Pickering emulsions with the water phase volume fraction of above 66.7 % were easily polymerized in situ at 70 °C without stirring. HNTs played an important role during Polymerization and effectively acted as building blocks for creating organic–inorganic nanocomposite microspheres after Polymerization. The sizes of PS/HNTs microspheres were roughly in accord with that of the corresponding emulsion droplets before Polymerization. The effect of the water phase volume fraction on the stability of Pickering emulsions and the morphologies of nanocomposite microspheres was investigated by optical microscopy, confocal laser scanning microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and so on.
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dual nanocomposite multihollow polymer microspheres prepared by Suspension Polymerization based on a multiple pickering emulsion
Polymer Chemistry, 2010Co-Authors: Quanxing Gao, Chaoyang Wang, Hongxia Liu, Yunhua Chen, Zhen TongAbstract:A solid-stabilized multiple w/o/w or o/w/o emulsion was prepared in a two-step process. Various nanocomposite polymer microspheres with multihollow armored closed pores were fabricated easily by Suspension Polymerization of the multiple Pickering stabilized emulsions.
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facile fabrication of nanocomposite microspheres with polymer cores and magnetic shells by pickering Suspension Polymerization
Reactive & Functional Polymers, 2009Co-Authors: Chaoyang Wang, Yunhua Chen, Chengjin Zhang, Zhen TongAbstract:Abstract Pickering Suspension Polymerization was used to prepare magnetic polymer microspheres that have polymer cores enveloped by shells of magnetic nanoparticles. Styrene was emulsified in an aqueous dispersion of Fe3O4 nanoparticles using a high shear. The resultant Pickering oil-in-water (o/w) emulsion stabilized solely by magnetic nanoparticles was easily polymerized at 70 °C without stirring. Fe3O4 nanoparticles act as effective stabilizers during Polymerization and as building blocks for creating the organic–inorganic hybrid nanocomposite after Polymerization. The fabricated magnetic nanocomposites were characterized by FTIR, XRD, TGA, DSC, GPC, XPS and SEM. The structures of the polymer core and the nanoparticle shell were analyzed. We investigated the effects on the products of the weight of Fe3O4 nanoparticles used to stabilize the original Pickering emulsions. Pickering Suspension Polymerization provides a new route for the synthesis of a variety of hybrid nanocomposite microspheres with supracolloidal structures.
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Suspension Polymerization based on inverse pickering emulsion droplets for thermo sensitive hybrid microcapsules with tunable supracolloidal structures
Polymer, 2009Co-Authors: Quanxing Gao, Chaoyang Wang, Hongxia Liu, Chenhong Wang, Xinxing Liu, Zhen TongAbstract:Polymerization using Pickering emulsion droplets as reaction vessels is being developed to become a powerful tool for fabrication of hybrid polymer particles with supracolloidal structures. In this paper, two kinds of thermo-sensitive hybrid poly(N-isopropylacrylamide) (PNIPAm) microcapsules with supracolloidal structures were successfully prepared from Suspension Polymerization stabilized by SiO2 nanoparticles based on inverse Pickering emulsion droplets. SiO2 nanoparticles could self-assemble at liquid–liquid interfaces to form stable water-in-oil inverse Pickering emulsion. NIPAm monomers dissolving in suspended aqueous droplets were subsequently polymerized at different temperatures. The hollow microcapsules with SiO2/PNIPAm nanocomposite shells were obtained when the reaction temperature was above the lower critical solution temperature (LCST) of PNIPAm. While the core–shell microcapsules with SiO2 nanoparticles' shells and PNIPAm gel cores were produced when the Polymerization was conducted at the temperature lower than LCST using UV light radiation. The supracolloidal structures with different cores could be tuned by simply changing reaction temperature, which was confirmed by confocal laser scanning microscopy and scanning electron microscopy. The interesting properties of both microcapsules were their ability of reversibly swelling during drying/wetting cycles and responsive to temperature stimulus. Such functional microcapsules may find applications in double control release system due to the presence of the supracolloidal structures and thermo-sensitivity.
Gang Cheng - One of the best experts on this subject based on the ideXlab platform.
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synthesis and biological evaluation of pmma mmt nanocomposite as denture base material
Journal of Materials Science: Materials in Medicine, 2011Co-Authors: Junping Zheng, Qiang Su, Chen Wang, Gang ChengAbstract:Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ Suspension Polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.
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synthesis and biological evaluation of pmma mmt nanocomposite as denture base material
Journal of Materials Science: Materials in Medicine, 2011Co-Authors: Junping Zheng, Chen Wang, Gang Cheng, Ran Zhu, Jin Shi, Kangde YaoAbstract:Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ Suspension Polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.
Junping Zheng - One of the best experts on this subject based on the ideXlab platform.
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synthesis and biological evaluation of pmma mmt nanocomposite as denture base material
Journal of Materials Science: Materials in Medicine, 2011Co-Authors: Junping Zheng, Qiang Su, Chen Wang, Gang ChengAbstract:Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ Suspension Polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.
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synthesis and biological evaluation of pmma mmt nanocomposite as denture base material
Journal of Materials Science: Materials in Medicine, 2011Co-Authors: Junping Zheng, Chen Wang, Gang Cheng, Ran Zhu, Jin Shi, Kangde YaoAbstract:Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ Suspension Polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.
