Different-sized hollow SiO2 spheres of 249–1348 nm in diameter were successfully prepared by using Na2SiO3 as the precursor and using polystyrene and polystyrene-methyl acrylic acid latexes as the templates. The diam...Different-sized hollow SiO2 spheres of 249–1348 nm in diameter were successfully prepared by using Na2SiO3 as the precursor and using polystyrene and polystyrene-methyl acrylic acid latexes as the templates. The diameter and shell thickness of the hollow SiO2 spheres increase with increasing the latex template diameter at a given mass ratio of SiO2 to latex template. The diameter and shell thickness of the hollow SiO2 spheres also increase with increasing the mass ratios of SiO2 to latex template. The presence of carboxylic acid groups on the surfaces of polystyrene-methyl acrylic acid latex templates favors the formation of dense and uniform SiO2 shells. The hollow SiO2 sphere is constructed by mesoporous shell with large specific surface area. When glyphosate is used as a release model chemical, glyphosate release rate is tuned by varying the shell thickness.展开更多
In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly...In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.展开更多
A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size an...A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamic mechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviously improve the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhance the store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHC content increased. TEM shows that the prepared polymers were actually organic-inorganic nanocomposites, and these films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organic silicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperature than organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.展开更多
A very mild and extremely efficient hydrolysis method for transformation of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to polystyrene-b-poly(acrylic acid) (PS-b-PAA) was designed and carried out using more co...A very mild and extremely efficient hydrolysis method for transformation of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to polystyrene-b-poly(acrylic acid) (PS-b-PAA) was designed and carried out using more convenient and inexpensive chlorotrimethylsilane/sodium iodide as reagents. The hydrolysis product can self-assemble in aqueous media to give regular micelles with PS block forming the core and PAA block forming the corona, or in tetrahydrofuran (THF) to give reverse micelles with the hydrophilic block in the core.展开更多
基金Projects (11KJB530002, CX10B-259Z) supported by Research Funds from Jiangsu Provincial Department of Education, ChinaProject (10zxfk35) supported by Sichuan Province Nonmetallic Composites and Functional Materials Key Laboratory Project, China
文摘Different-sized hollow SiO2 spheres of 249–1348 nm in diameter were successfully prepared by using Na2SiO3 as the precursor and using polystyrene and polystyrene-methyl acrylic acid latexes as the templates. The diameter and shell thickness of the hollow SiO2 spheres increase with increasing the latex template diameter at a given mass ratio of SiO2 to latex template. The diameter and shell thickness of the hollow SiO2 spheres also increase with increasing the mass ratios of SiO2 to latex template. The presence of carboxylic acid groups on the surfaces of polystyrene-methyl acrylic acid latex templates favors the formation of dense and uniform SiO2 shells. The hollow SiO2 sphere is constructed by mesoporous shell with large specific surface area. When glyphosate is used as a release model chemical, glyphosate release rate is tuned by varying the shell thickness.
文摘In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.
基金Supported by the National "863" Project (No. 2001 AA 320206)and Shanghai Nano Special Foundation(No. 0120nm034).
文摘A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamic mechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviously improve the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhance the store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHC content increased. TEM shows that the prepared polymers were actually organic-inorganic nanocomposites, and these films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organic silicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperature than organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.
基金National Natural Scientific Foundation of China. (Project grant No. 29936100)
文摘A very mild and extremely efficient hydrolysis method for transformation of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to polystyrene-b-poly(acrylic acid) (PS-b-PAA) was designed and carried out using more convenient and inexpensive chlorotrimethylsilane/sodium iodide as reagents. The hydrolysis product can self-assemble in aqueous media to give regular micelles with PS block forming the core and PAA block forming the corona, or in tetrahydrofuran (THF) to give reverse micelles with the hydrophilic block in the core.
