Molecularly imprinted polymers using 2,4-dichlorophenoxyacetic acid (2,4-D) as templates were prepared by suspension polymerization in silicon oil. The polymer particles exhibited regular shape in the micro-scale ra...Molecularly imprinted polymers using 2,4-dichlorophenoxyacetic acid (2,4-D) as templates were prepared by suspension polymerization in silicon oil. The polymer particles exhibited regular shape in the micro-scale range. The adsorbing experiments indicated that the imprinted polymer particles possessed higher affinity to 2,4-D than the non-imprinted polymer particles.展开更多
Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by est...Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.展开更多
Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.I...Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.In the present contribution,n-dodecane/PMMA microencapsulated phase change materials were prepared by suspension polymerization for ice-temperature cold chain transportation and their preparation parameters were explored using the encapsulation ratio as optimization indicator.The results show that the n-dodecane-containing microcapsules have a maximum encapsulation ratio of 93.2%when using a core-to-wall ratio of 3:1,5%of emulsifier,30%of crosslinker,and 2000 rpm of emulsification speed.The phase transition temperature and enthalpy are-2℃and 195.9 kJ/kg,respectively.The microcapsules prepared with the optimized process parameters have good microscopic morphology,high energy storage efficiency,uniform particle size and good thermal stability,making them ideal materials for cold chain transportation.展开更多
Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres synthesized by suspension polymerization were used as supports for palladium catalyst.The results showed the novel magnetic catalyst can promote Heck reaction of a...Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres synthesized by suspension polymerization were used as supports for palladium catalyst.The results showed the novel magnetic catalyst can promote Heck reaction of aryl halides with acrylic acid efficiently without an inert atmosphere.In addition,the novel catalyst can be conveniently recovered by applying an external magnet and reused at least five times without significant loss of its activity.展开更多
A series of acrylic-based superabsorbent resins were synthesized by inverse suspension polymerization, using potassium persulfate as the initiator, N, N'-methylene bisacrylamide (BIS) and divinylbenzene (DVB) as ...A series of acrylic-based superabsorbent resins were synthesized by inverse suspension polymerization, using potassium persulfate as the initiator, N, N'-methylene bisacrylamide (BIS) and divinylbenzene (DVB) as the multiple crosslinking agents. The morphology of the resulting superabsorbent resins revealed by SEM demonstrated that a hard shell layer was indeed formed due to surface crosslinking. The swelling and deswelling properties, and the mechanical strength of superabsorbents were investigated. The results indicated that the adding time of DVB and the amount of DVB participated in the crosslinking show a significant influence on the properties of superabsorbents. When DVB was added in polymerization later, the amount of DVB participated in reaction decreases and the surface crosslinked shell becomes thinner. It is suitable for DVB to be introduced in the later stage of the polymerization process, because the absorption rate of resin is efficiently improved in conjunction with higher water absorption. Furthermore, it was found that the mechanical strength of swollen superabsorbent with surface crosslinking was indeed enhanced in comparison with that of the conventional one.展开更多
The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate (GMA)/methacrylamide(MA)/N,N'-methylene-bis(acrylamide)(MBAA)was synthesized using the industrial agents by inverse suspensio...The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate (GMA)/methacrylamide(MA)/N,N'-methylene-bis(acrylamide)(MBAA)was synthesized using the industrial agents by inverse suspension polymerization. The apparent activity of the immobilized penicillin G acylase reached 1096 IU/g for hydrolysis penicillin G on the beads with diameter of 0.11-0.13 ram, and it changed hardly after 50 cycles. It can be expected to be a good potential in industrial application,展开更多
An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and sus...An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.展开更多
Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recov...Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P(AM-BA-AMCO), which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.展开更多
The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation cond...The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation conditions, the shape and position of stirrers, and stirring rate etc., have important influence on the size and distribution of particles. The preparation conditions must be carefully designed and controlled in order to obtain high-quality PS beads. A bow-shaped stirrer is helpful to produce small-sized particles and narrow size distribution, and the upper edge of a stirrer should be set to the same level as the surface of mixture, and the stirring rate should be controlled in the range of 520-600 r/min.展开更多
Polystyrene (PS)/triphenyl phosphate (TPP) composites were prepared by both suspension polymerization and melt extrusion, and a comparative study of the flame retardance and mechanical properties was carried out. ...Polystyrene (PS)/triphenyl phosphate (TPP) composites were prepared by both suspension polymerization and melt extrusion, and a comparative study of the flame retardance and mechanical properties was carried out. The results showed that suspension polymerization was a better technique than melt extrusion for obtaining good dispersity of the PS/TPP composite. The TPP nanoparticles, which were approximately 50 nm in size, were homogenously and uniformly dispersed in the PS matrix by suspension polymerization in one-step. However, the PS/TPP composite was partially agglomerated, exhibiting irregularly shaped micron-scale particles as a result of melt extrusion. In contrast to the melt extrusion, the limited oxygen index (LOI) of the PS/TPP nanocomposite by suspension polymerization increased to 22.6% from 21.8%, and time to ignition (TTI) increased by 12.3%, the peak heat release rate (PHRR) decreased by 8.5%, and the total heat release (THR) decreased by 11.0%. The mechanical properties of the PS/TPP nanocomposite by suspension polymerization also increased. The tensile strength, elongation at break, and flexural strength increased by 36.4%, 8.5%, and 108%, respectively.展开更多
A kind of fibrous clay, palygorskite (PAL), was used as the sole stabilizer in suspension polymerization without the using of any other stabilizer usually used, especially polymeric stabilizers. In order to improve ...A kind of fibrous clay, palygorskite (PAL), was used as the sole stabilizer in suspension polymerization without the using of any other stabilizer usually used, especially polymeric stabilizers. In order to improve the compatibility with the organic monomer, PAL nano fibers were organically modified with silane coupling agent methacryloxypropyltrimethoxysilane (MPS). Transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) spectroscopy results show that the hydrolyzed MPS was attached onto PAL surface through Si--O--Si bonds formation without morphology change of PAL. At a loading amount of PAL to monomer as low as 0.36 wt%, effective stabilization could be achieved. After suspension polymerization, spherical poly(methyl methacrylate) (PMMA) particles were obtained. Scanning electron microscopy (SEM) analysis on both the outer surface and the inner cracked surface of the spherical PMMA particles indicates that the PAL particles reside on the surface of the PMMA spheres. The densely stacked PAL together with attached silane coupling agent stabilized the droplets throughout the suspension polymerization.展开更多
The porous hydroxyapatite(HAP)for suspen-sion polymerization dispersant was prepared using calcium carbonate and phosphoric acid as raw materials.The samples were characterized by scanning electron micro-scopy(SEM),X-...The porous hydroxyapatite(HAP)for suspen-sion polymerization dispersant was prepared using calcium carbonate and phosphoric acid as raw materials.The samples were characterized by scanning electron micro-scopy(SEM),X-ray diffraction(XRD)and BET nitrogen adsorption.The results show that the prepared HAP has a porous structure,low particle density,large specific surface area,uniform particle size and does not agglomerate easily between the particles.The preparation conditions for the HAP were optimized as follows:solid content of calcium carbonate aqueous suspension 90 g/L,concentration of phosphoric acid 1.0 mol/L,reaction/aging temperature 50℃,and aging time 3 h.The HAP prepared under optimal preparation conditions has 106.8 m^(2)·g 21 of specific surfacearea,whichisabout1.5–1.8timesasmuchasthatof JapaneseHAPorcommercialHAP.Itsapplicationresultin the suspension polymerization of styrene show that the porous HAP dispersant has high surface activity,excellent suspension dispersibility and stability and can markedly improve the quality of polystyrene beads.展开更多
In this paper, thermoexpandable polymeric microspheres were prepared by suspension polymerization with acrylonitrile (AN) and methyl methacrylate (MMA) as monomers and/-butane as a blowing agent. The micromorpholo...In this paper, thermoexpandable polymeric microspheres were prepared by suspension polymerization with acrylonitrile (AN) and methyl methacrylate (MMA) as monomers and/-butane as a blowing agent. The micromorphology and thermal stability were researched by polarized microscopy and TGA. The diameter of the expandable microspheres increased from about 20μm (unexpanded) to 40-80 μm (expanded) upon heating. The maximum expansion volume was higher than 22 times of the original volume and the density of the expanded microspheres was about 16.7 kg/m3. The blowing agent content in microspheres was about 20 wt% and To.e., Tm.e. and To.s. were 80℃, 120-130℃ and 140-145℃, respectively.展开更多
Superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (Pst-DVB-GMA) microparticles were prepared via a modified suspension polymerization process. A magnetic fluid was first prepared by a chemical co-pr...Superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (Pst-DVB-GMA) microparticles were prepared via a modified suspension polymerization process. A magnetic fluid was first prepared by a chemical co-precipitation method. Then magnetic microparticles were produced by mixing the monomers and the magnetic fluid with water in the presence of a stabilizer poly(vinyl pyrrolidone) (PVP) to form a suspension, and finally benzoyl peroxide was added to initiate the co-polymerization. The morphology and magnetic properties of the microparticles were examined by TEM and VSM. The spherically shaped microparticles, with a size range of 4 to 7 urn, showed distinct Superparamagnetic characteristics. XRD was used to investigate the structure of the magnetite particles dispersed in the polymer matrix. The microparticles with epoxy groups on their surface can be applied directly to the separation of biomolecules.展开更多
Macroreticular ion exchange resin catalysts were prepared by suspension polymerization, and then modified by alkylmercaptoamines. The modified catalysts were characterized by N2 adsorption/desorption measure- ments, s...Macroreticular ion exchange resin catalysts were prepared by suspension polymerization, and then modified by alkylmercaptoamines. The modified catalysts were characterized by N2 adsorption/desorption measure- ments, scanning electron microscopy and differential scanning calorimetry. Key factors such as the mercaptan content, the degree of crosslinking and the structures of the promoters were investigated for the synthesis of Bisphenol A (BPA). At optimal conditions, the macroreticular ion exchange resin catalysts modified by alkylmercaptoamines showed high catalytic activity and selectivity for BPA synthesis.展开更多
The thermally expandable microspheres(TEMs) were prepared via suspension polymerization with acrylonitrile(AN), methyl methacrylate(MMA) and methyl acrylate(MA) as monomers and n-hexane as the blowing agent. M...The thermally expandable microspheres(TEMs) were prepared via suspension polymerization with acrylonitrile(AN), methyl methacrylate(MMA) and methyl acrylate(MA) as monomers and n-hexane as the blowing agent. Meanwhile, a novel type of functional and conductive thermal expandable microsphere was obtained through strongly covering the surface of microsphere by conductive polymers with the mass loading of 1.5%. The optimal conditions to prepare high foaming ratio and equally distributed microcapsules were investigated with AN-MMA-MA in the proportion of 70%/20%/10%(m/m/m), and 25 wt% of n-hexane in oil phase. The further investigation results showed that the unexpanded TEMs were about 30 μm in diameter and the maximum expansion ratio was nearly 125 times of original volume. The polypyrrole(PPy) was smoothly coated on the surface of the TEMs and the expansion property of PPy-coated TEMs was almost the same as the uncoated TEMs. Moreover, the structure and expanding performance of TEMs and PPy-coated TEMs were characterized by scanning electron microscopy(SEM), laser particle size analyzer and dilatometer(DIL).展开更多
基金supported by the National Natural Science Foundation of China(No 20274052).
文摘Molecularly imprinted polymers using 2,4-dichlorophenoxyacetic acid (2,4-D) as templates were prepared by suspension polymerization in silicon oil. The polymer particles exhibited regular shape in the micro-scale range. The adsorbing experiments indicated that the imprinted polymer particles possessed higher affinity to 2,4-D than the non-imprinted polymer particles.
基金This work was supported by the National 973 project (G1999064707)
文摘Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.
基金supported by the National Key Research and Development Program of china(No.2018YFD1101005)and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.In the present contribution,n-dodecane/PMMA microencapsulated phase change materials were prepared by suspension polymerization for ice-temperature cold chain transportation and their preparation parameters were explored using the encapsulation ratio as optimization indicator.The results show that the n-dodecane-containing microcapsules have a maximum encapsulation ratio of 93.2%when using a core-to-wall ratio of 3:1,5%of emulsifier,30%of crosslinker,and 2000 rpm of emulsification speed.The phase transition temperature and enthalpy are-2℃and 195.9 kJ/kg,respectively.The microcapsules prepared with the optimized process parameters have good microscopic morphology,high energy storage efficiency,uniform particle size and good thermal stability,making them ideal materials for cold chain transportation.
文摘Macroporous magnetic poly(GMA-EGDMA-DVB) microspheres synthesized by suspension polymerization were used as supports for palladium catalyst.The results showed the novel magnetic catalyst can promote Heck reaction of aryl halides with acrylic acid efficiently without an inert atmosphere.In addition,the novel catalyst can be conveniently recovered by applying an external magnet and reused at least five times without significant loss of its activity.
文摘A series of acrylic-based superabsorbent resins were synthesized by inverse suspension polymerization, using potassium persulfate as the initiator, N, N'-methylene bisacrylamide (BIS) and divinylbenzene (DVB) as the multiple crosslinking agents. The morphology of the resulting superabsorbent resins revealed by SEM demonstrated that a hard shell layer was indeed formed due to surface crosslinking. The swelling and deswelling properties, and the mechanical strength of superabsorbents were investigated. The results indicated that the adding time of DVB and the amount of DVB participated in the crosslinking show a significant influence on the properties of superabsorbents. When DVB was added in polymerization later, the amount of DVB participated in reaction decreases and the surface crosslinked shell becomes thinner. It is suitable for DVB to be introduced in the later stage of the polymerization process, because the absorption rate of resin is efficiently improved in conjunction with higher water absorption. Furthermore, it was found that the mechanical strength of swollen superabsorbent with surface crosslinking was indeed enhanced in comparison with that of the conventional one.
基金supported by the National Natural Science Foundation of China(No.20564002)the State Key Program of Fundamental Research(No.2004CCA05900).
文摘The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate (GMA)/methacrylamide(MA)/N,N'-methylene-bis(acrylamide)(MBAA)was synthesized using the industrial agents by inverse suspension polymerization. The apparent activity of the immobilized penicillin G acylase reached 1096 IU/g for hydrolysis penicillin G on the beads with diameter of 0.11-0.13 ram, and it changed hardly after 50 cycles. It can be expected to be a good potential in industrial application,
文摘An overview of aqueous polymerizations, which include emulsion, miniemulsion and suspension polymerizations, under stable free radical polymerization (SFRP) conditions is presented. The success of miniemulsion and suspension SFRP polymerizations is contrasted with the difficulties associated with obtaining a stable emulsion polymerization. A recently developed unique microprecipitation technique is referenced as a means of making submicron sized particles that can be used to achieve a stable emulsion SFRP process.
基金supported by the National Natural Science Foundation of China (No.21273286)Doctoral Program Foundation of the Education Ministry (No.20130133110005)
文摘Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P(AM-BA-AMCO), which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.
文摘The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation conditions, the shape and position of stirrers, and stirring rate etc., have important influence on the size and distribution of particles. The preparation conditions must be carefully designed and controlled in order to obtain high-quality PS beads. A bow-shaped stirrer is helpful to produce small-sized particles and narrow size distribution, and the upper edge of a stirrer should be set to the same level as the surface of mixture, and the stirring rate should be controlled in the range of 520-600 r/min.
文摘Polystyrene (PS)/triphenyl phosphate (TPP) composites were prepared by both suspension polymerization and melt extrusion, and a comparative study of the flame retardance and mechanical properties was carried out. The results showed that suspension polymerization was a better technique than melt extrusion for obtaining good dispersity of the PS/TPP composite. The TPP nanoparticles, which were approximately 50 nm in size, were homogenously and uniformly dispersed in the PS matrix by suspension polymerization in one-step. However, the PS/TPP composite was partially agglomerated, exhibiting irregularly shaped micron-scale particles as a result of melt extrusion. In contrast to the melt extrusion, the limited oxygen index (LOI) of the PS/TPP nanocomposite by suspension polymerization increased to 22.6% from 21.8%, and time to ignition (TTI) increased by 12.3%, the peak heat release rate (PHRR) decreased by 8.5%, and the total heat release (THR) decreased by 11.0%. The mechanical properties of the PS/TPP nanocomposite by suspension polymerization also increased. The tensile strength, elongation at break, and flexural strength increased by 36.4%, 8.5%, and 108%, respectively.
基金financially supported by the Bureau of Construction of Gansu Province(No.201169)the Bureau of Education of Gansu Province(No.20727)
文摘A kind of fibrous clay, palygorskite (PAL), was used as the sole stabilizer in suspension polymerization without the using of any other stabilizer usually used, especially polymeric stabilizers. In order to improve the compatibility with the organic monomer, PAL nano fibers were organically modified with silane coupling agent methacryloxypropyltrimethoxysilane (MPS). Transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) spectroscopy results show that the hydrolyzed MPS was attached onto PAL surface through Si--O--Si bonds formation without morphology change of PAL. At a loading amount of PAL to monomer as low as 0.36 wt%, effective stabilization could be achieved. After suspension polymerization, spherical poly(methyl methacrylate) (PMMA) particles were obtained. Scanning electron microscopy (SEM) analysis on both the outer surface and the inner cracked surface of the spherical PMMA particles indicates that the PAL particles reside on the surface of the PMMA spheres. The densely stacked PAL together with attached silane coupling agent stabilized the droplets throughout the suspension polymerization.
文摘The porous hydroxyapatite(HAP)for suspen-sion polymerization dispersant was prepared using calcium carbonate and phosphoric acid as raw materials.The samples were characterized by scanning electron micro-scopy(SEM),X-ray diffraction(XRD)and BET nitrogen adsorption.The results show that the prepared HAP has a porous structure,low particle density,large specific surface area,uniform particle size and does not agglomerate easily between the particles.The preparation conditions for the HAP were optimized as follows:solid content of calcium carbonate aqueous suspension 90 g/L,concentration of phosphoric acid 1.0 mol/L,reaction/aging temperature 50℃,and aging time 3 h.The HAP prepared under optimal preparation conditions has 106.8 m^(2)·g 21 of specific surfacearea,whichisabout1.5–1.8timesasmuchasthatof JapaneseHAPorcommercialHAP.Itsapplicationresultin the suspension polymerization of styrene show that the porous HAP dispersant has high surface activity,excellent suspension dispersibility and stability and can markedly improve the quality of polystyrene beads.
基金supported by Shandong Provincial Natural Science Foundation,China (No.ZR2013EMM004)
文摘In this paper, thermoexpandable polymeric microspheres were prepared by suspension polymerization with acrylonitrile (AN) and methyl methacrylate (MMA) as monomers and/-butane as a blowing agent. The micromorphology and thermal stability were researched by polarized microscopy and TGA. The diameter of the expandable microspheres increased from about 20μm (unexpanded) to 40-80 μm (expanded) upon heating. The maximum expansion volume was higher than 22 times of the original volume and the density of the expanded microspheres was about 16.7 kg/m3. The blowing agent content in microspheres was about 20 wt% and To.e., Tm.e. and To.s. were 80℃, 120-130℃ and 140-145℃, respectively.
基金This work was financially supported by the National High Technology Research and Development Program of China(No.2002AA302211)the National Natural Science Foundation of China(No.20206032).
文摘Superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (Pst-DVB-GMA) microparticles were prepared via a modified suspension polymerization process. A magnetic fluid was first prepared by a chemical co-precipitation method. Then magnetic microparticles were produced by mixing the monomers and the magnetic fluid with water in the presence of a stabilizer poly(vinyl pyrrolidone) (PVP) to form a suspension, and finally benzoyl peroxide was added to initiate the co-polymerization. The morphology and magnetic properties of the microparticles were examined by TEM and VSM. The spherically shaped microparticles, with a size range of 4 to 7 urn, showed distinct Superparamagnetic characteristics. XRD was used to investigate the structure of the magnetite particles dispersed in the polymer matrix. The microparticles with epoxy groups on their surface can be applied directly to the separation of biomolecules.
文摘Macroreticular ion exchange resin catalysts were prepared by suspension polymerization, and then modified by alkylmercaptoamines. The modified catalysts were characterized by N2 adsorption/desorption measure- ments, scanning electron microscopy and differential scanning calorimetry. Key factors such as the mercaptan content, the degree of crosslinking and the structures of the promoters were investigated for the synthesis of Bisphenol A (BPA). At optimal conditions, the macroreticular ion exchange resin catalysts modified by alkylmercaptoamines showed high catalytic activity and selectivity for BPA synthesis.
基金the National Natural ScienceFoundation of China(Nos.21206171,21376010)the Project of Natural Science Foundation of Beijing(No.2152012)+1 种基金the Young Elite Teacher Project(No.27170115004/027)the Project of 2011 Collaborative Innovation for Green Printing and Publishing Technology and the Project of Beijing Municipal Commission of Educatio (No.km201410005007)for the financial supports
文摘The thermally expandable microspheres(TEMs) were prepared via suspension polymerization with acrylonitrile(AN), methyl methacrylate(MMA) and methyl acrylate(MA) as monomers and n-hexane as the blowing agent. Meanwhile, a novel type of functional and conductive thermal expandable microsphere was obtained through strongly covering the surface of microsphere by conductive polymers with the mass loading of 1.5%. The optimal conditions to prepare high foaming ratio and equally distributed microcapsules were investigated with AN-MMA-MA in the proportion of 70%/20%/10%(m/m/m), and 25 wt% of n-hexane in oil phase. The further investigation results showed that the unexpanded TEMs were about 30 μm in diameter and the maximum expansion ratio was nearly 125 times of original volume. The polypyrrole(PPy) was smoothly coated on the surface of the TEMs and the expansion property of PPy-coated TEMs was almost the same as the uncoated TEMs. Moreover, the structure and expanding performance of TEMs and PPy-coated TEMs were characterized by scanning electron microscopy(SEM), laser particle size analyzer and dilatometer(DIL).