Core-shell colloidal particles with a polymer layer have broad applications in different areas.Herein,we developed a two-step method combining aqueous surface-initiated photoinduced polymerization-induced self-assembl...Core-shell colloidal particles with a polymer layer have broad applications in different areas.Herein,we developed a two-step method combining aqueous surface-initiated photoinduced polymerization-induced self-assembly and photoinduced seeded reversible addition-fragmentation chain transfer(RAFT)polymerization to prepare a diverse set of core-shell colloidal particles with a well-defined polymer layer.Chemical compositions,structures,and thicknesses of polymer layers could be conveniently regulated by using different types of monomers and feed[monomer]/[chain transfer agent]ratios during seeded RAFT polymerization.展开更多
Vinyl acetate radical emulsion polymerization in water with GF51 silane co-monomer was performed by semi continuous way. The GF51 impacts on dispersion rheology as well on films and bonding strength properties were de...Vinyl acetate radical emulsion polymerization in water with GF51 silane co-monomer was performed by semi continuous way. The GF51 impacts on dispersion rheology as well on films and bonding strength properties were determined. It should be stated that even low quantities of GF51 （up to 6% from VAc） determined high viscosity of dispersions. The GF51 modified films have low water absorption and high affinity to glass. Molecular mass and thermal properties of GF51 modified polymers were determined accordingly.展开更多
Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed p...Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.展开更多
Micron-sized nonspherical polymer particles having different morphologies were synthesized by seeded soap-free emulsion polymerization of styrene （St） and ethyleneglycol dimethacrylate （EGDMA, used as a crosslinker...Micron-sized nonspherical polymer particles having different morphologies were synthesized by seeded soap-free emulsion polymerization of styrene （St） and ethyleneglycol dimethacrylate （EGDMA, used as a crosslinker） on spherical, linear polystyrene （PS） seed particles. The morphology of the resulting PS/poly（St-co-EGDMA） particles was dependent on the crosslinker concentration and polymerization temperature.展开更多
The doubly thermo-responsive triblock copolymer nanoparticles of polystyrene-block-poly（N- isopropylacrylamide）-block-poly[N,N-（dimethylamino） ethyl methacrylate] （PS-b-PNIPAM-b-PDMAEMA） are successfully prepare...The doubly thermo-responsive triblock copolymer nanoparticles of polystyrene-block-poly（N- isopropylacrylamide）-block-poly[N,N-（dimethylamino） ethyl methacrylate] （PS-b-PNIPAM-b-PDMAEMA） are successfully prepared through the seeded RAFT polymerization in situ by using the PS-b-PNIPAM-TTC diblock copolymer nanoparticles as the seed. The seeded RAFT polymerization undergoes a pseudo-first-order kinetics procedure, and the molecular weight increases with the monomer conversion linearly. The hydrodynamic diameter （Dh） of the triblock copolymer nanoparticles increases with the extension of the PDMAEMA block. In addition, the double thermo-response behavior of the PS-b-PNIPAM-b-PDMAEMA nanoparticles is detected by turbidity analysis, temperature-dependent 1H-NMR analysis, and DLS analysis. The seeded RAFT polymerization is believed as a valid method to prepare triblock copolymer nanoparticles containing two thermo-responsive blocks.展开更多
In this study, P（St-MAA） seed latex particles were first prepared via soap-free emulsion polymerization of styrene （St） and methacrylic acid （MAA）, then the seed particles were allowed to swell with St at room t...In this study, P（St-MAA） seed latex particles were first prepared via soap-free emulsion polymerization of styrene （St） and methacrylic acid （MAA）, then the seed particles were allowed to swell with St at room temperature, and the P（St-MAA）/P（St- NaSS） core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate （NaSS） using AIBN as initiator in the presence of N,N^-methylenebisacrylamide （BAA, water-soluble crosslinker）. Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%, the narrow dispersed P（St-MAA） seed particles with the diameter of 150 nm and the P（St-MAA）/P（St-NaSS） core/shell latexes with the particle size of about 200 nm were synthesized. When the 25/75 mole ratio of NaSS/（St ＋ MAA） and 2 tool% of BAA were used in the seeded emulsion polymerization, the resulted P（St-MAA）/P（St-NaSS） latex product showed a low weight loss after water extraction, and the NaSS unit content in the whole particle and in the shell reached 11.7 mol% and 34.6 mol%, resoectivelv.展开更多
The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare th...The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solid content. The effects of monomer emulsion feed rates (R(a)) and (R/E)(E) values, the ratio of emulsifier amount between the initial charge (R) and the addition monomer emulsion (E), on the polymerization reaction features, the viscosities, surface tensions,particle sizes and particle sizes distributions of latexes, T-g and the insoluble fractions of films, the 180 degrees peel strength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, prepared from the latexes, were studied. Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180 degrees peel strength, tack and holding power.展开更多
Poly（methyl methacrylate）/poly（N-isopropylacrylamide） （PMMA/PNIPAM） core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide （NIPAM） in the presence of PMMA seed pa...Poly（methyl methacrylate）/poly（N-isopropylacrylamide） （PMMA/PNIPAM） core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide （NIPAM） in the presence of PMMA seed particles. The anionic potassium persulfate was used as initiator, and acrylic acid as functional comonomer. It was shown that the weight ratio of the PNIPAM shell to the PMMA core can be greatly increased through continuous addition of NIPAM monomer at a relatively slow rate. PMMA/PNIPAM particles with different shell thickness were obtained by varying the amount of charged NIPAM monomers. These particles exhibited unique nonspherical core-shell morphology. PMMA core was partially coated by dense hair-like or antler-like PNIPAM shell depending on the shell thickness. The measurement of these particles＇ zeta potential at different temperatures showed that the absolute value of zeta potential unusually decreased as the particle size decreased with temperature.展开更多
A highly crosslinked, monodispersed polystyrene（PS） particle was prepared by a seeded batch dispersion polymerization with a monomer absorption method. Prior to polymerization, 1,9 lam monodispersed PS seed particle...A highly crosslinked, monodispersed polystyrene（PS） particle was prepared by a seeded batch dispersion polymerization with a monomer absorption method. Prior to polymerization, 1,9 lam monodispersed PS seed particles were treated under an optimum condition of monomer absorption. The effects of divinylbenzebe（DVB） concentration and polymerization temperature were examined for styrene（in PS seed）/styrene（in the second stage） mass ratio of 1：1 in the medium range of EtOH/water mass ratio of 100/0-80/20 and 2.3 μm uniform crosslinked PS particles containing 15%-20% （mass fraction） DVB were prepared at 60-70 ℃. The results show that monomer absorption before the second stage of polymerization is more effective to prepare highly crosslinked monodispersed PS particles.展开更多
Microspheres based on binary polymer blend consisting of polystyrene (PSt), poly (methyl methacrylate) (PMMA), block copolymer comprising PSt and PMMA subunits, and ternary polymer blend consisting of PSt, PMMA, and b...Microspheres based on binary polymer blend consisting of polystyrene (PSt), poly (methyl methacrylate) (PMMA), block copolymer comprising PSt and PMMA subunits, and ternary polymer blend consisting of PSt, PMMA, and block copolymer were fabricated by a solvent evaporation method, in which a polymer solution in dichloromethane was dispersed in water phase with the aid of a homogenizer to obtain an O/W emulsion followed by solvent evaporation with agitation to solidify the polymer. In the case of ternary blend, the effect of block copolymer content on the morphology of resulting spheres was investigated. Ternary blends afforded the bi-compartmental morphologies, the intermediate morphology between Janus and core-shell, which was confirmed by TEM observation. Seed polymerization of St or MMA was also carried out utilizing the resulting microspheres as seed particles in order to control the shape, and the surface morphology of particles. The particles with snowman-like morphology were obtained by seed polymerization of St using PSt/PMMA binary blend microspheres as seed particles. Surface roughness was controlled by the polymerization of MMA in the block copolymer seed, and that of St in the ternary blend seed.展开更多
Coating seeds with water absorbent materials can improve their survival, especially for those planted in drought or barren areas. In this study, effects of five kinds of super absorbent polymers(SAPs) on seed germinat...Coating seeds with water absorbent materials can improve their survival, especially for those planted in drought or barren areas. In this study, effects of five kinds of super absorbent polymers(SAPs) on seed germination and seedling growth of Caragana korshinskii under drought conditions were investigated. Our results showed that SAP coatings could significantly improve the percentage and energy of seed germination, as well as reduce the relative electrical conductivity(REC), proline, malondialdehyde(MDA), H_2O_2 content, and peroxidase(POD) activity during germination. These results implied that seeds could uptake moisture from SAP coatings to alleviate drought-induced oxidative stress and membrane damage, thus exhibiting a better vigor and germination performance. After coating C. korshinskii seeds with SAPs, more seedlings emerged and grew better. Under the combined influence of the water absorption capacity of SAP and other factors, the efficiencies of five SAP coatings are in the sequence D>E>B>A>C. The function of the SAP coating on promoting seedling survival was confirmed in Mu Us Sandy Land in Ordos, Inner Mongolia Autonomous Region, China. The average seedling number of SAP D-coated seeds increased twofold on that of naked seeds. Our results are expected to be helpful in understanding and utilizing SAP seed coatings in improving plant survival under drought conditions.展开更多
Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles f...Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles formed at last. The shape was observed by SEM. These particles became ball-like when swollen by toluene, observed by optical microscope, and the release behavior of solvent from them was examined.展开更多
The traditional method to refine crude cottonseed oil is time-consuming and expensive.This study evaluates the effectiveness of coagulation–flocculation–sedimentation process using quaternary polyamine-based polymer...The traditional method to refine crude cottonseed oil is time-consuming and expensive.This study evaluates the effectiveness of coagulation–flocculation–sedimentation process using quaternary polyamine-based polymers in refining crude cottonseed oil.Flocculated by four commercial polyamine-based cationic polymers(SL2700,SL3000,SL4500 and SL5000)with varied molecular weight(MW)and charge density(CD)and followed by coagulation with sodium hydroxide,crude cottonseed oil can be effectively purified.Free fatty acids,gossypol,pigments and trace elements are all effectively and sufficiently removed by the four polymers in a MW-and CDdependent manner.Our results suggest that the use of polyamine-based cationic polymers may offer an effective and feasible alternative to the traditional method for crude cottonseed oil refining.展开更多
Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was sw...Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was swollen by toluene, and then the mixture of second monomers was added under polymerization condition. So a thin shell of poly(styrene-glycidyl methacrylate) cross-linked by triethylene glycol diacrylate was formed around the swollen PS particle. The bowl-shaped particles were obtained after the collapsing of the thin shell when the toluene emanated from the particles, but the shapes were effected by the degrees of cross-linking. The shape of the particles was observed by SEM. The release behavior of solvent from the particles was examined by TG.展开更多
The objective of this work was to analyze the effects of the polymerization temperature on the kinetic features(instantaneous and overall conversions)and colloidal characteristics[mean particle diameter,stabilities]in...The objective of this work was to analyze the effects of the polymerization temperature on the kinetic features(instantaneous and overall conversions)and colloidal characteristics[mean particle diameter,stabilities]in the semicontinuous seeded cationic emulsion polymerization of styrene and butyl acrylate.Azobis is obutyl amidine hydrochloride was used as an initiator.The surfactants wascetyl trimethyl ammonium chloride.The results showed that the final instant when the polymerization temperature of 85℃emulsion highest conversion rate,and the temperature of the emulsion particle size,centrifugal stability is the best,85℃emulsion in the emulsion anti-dilution and acid salt stability also showed excellent stability.展开更多
A series of poly（2-acetoxyethyl methacrylate）/polystyrene（PAEMA/PS） latex interpenetrating polymer networks（LIPNs） were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA se...A series of poly（2-acetoxyethyl methacrylate）/polystyrene（PAEMA/PS） latex interpenetrating polymer networks（LIPNs） were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator.These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase.The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.展开更多
Crosslinked x-P（St-MAA） seed latex was first prepared via soap-free emulsion copolymerization of styrene （St） and methyl methacrylic acid （MAA） with divinyl benzene as crosslinker and ammonium persulfate as init...Crosslinked x-P（St-MAA） seed latex was first prepared via soap-free emulsion copolymerization of styrene （St） and methyl methacrylic acid （MAA） with divinyl benzene as crosslinker and ammonium persulfate as initiator, and x-P（St-MAA）/x-P（St-NaSS） core/shell latex particles were then synthesized through a novel seeded emulsion copolymerization of St and sodium styrene sulphonate （NaSS） in the presence of water-soluble crosslinker N,N＇-methylene bisacrylamide （BAA） using oil-soluble 2,2-azobis isobutyronitrile as initiator. TEM observation indicated that narrow dispersed core/shell latex particles were obtained, and element analysis showed that NaSS unit content in the whole particle and in the shell reached 22.8 wt% and 51.2 wt%, respectively.展开更多
Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerizat...Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerization still constitutes a challenge.Herein,the kinetically controlled supramolecular polymerization of porphyrin derivatives was achieved in aqueous media by a seeding method based on a metastable state generated by synergistic metalation and Lewis acid–base complexation.展开更多
基金support from the Science and Technology Program of Guangzhou(No.2024A04J2821)the National Natural Science Foundation of China(Nos.52222301,22171055)the Guangdong Natural Science Foundation for Distinguished Young Scholar(No.2022B1515020078)。
文摘Core-shell colloidal particles with a polymer layer have broad applications in different areas.Herein,we developed a two-step method combining aqueous surface-initiated photoinduced polymerization-induced self-assembly and photoinduced seeded reversible addition-fragmentation chain transfer(RAFT)polymerization to prepare a diverse set of core-shell colloidal particles with a well-defined polymer layer.Chemical compositions,structures,and thicknesses of polymer layers could be conveniently regulated by using different types of monomers and feed[monomer]/[chain transfer agent]ratios during seeded RAFT polymerization.
文摘Vinyl acetate radical emulsion polymerization in water with GF51 silane co-monomer was performed by semi continuous way. The GF51 impacts on dispersion rheology as well on films and bonding strength properties were determined. It should be stated that even low quantities of GF51 （up to 6% from VAc） determined high viscosity of dispersions. The GF51 modified films have low water absorption and high affinity to glass. Molecular mass and thermal properties of GF51 modified polymers were determined accordingly.
基金supported by National Natural Science Foundation of China(No.50943028)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.
基金partially supported by the National Natural Science Foundation of China(No.50943028)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Micron-sized nonspherical polymer particles having different morphologies were synthesized by seeded soap-free emulsion polymerization of styrene （St） and ethyleneglycol dimethacrylate （EGDMA, used as a crosslinker） on spherical, linear polystyrene （PS） seed particles. The morphology of the resulting PS/poly（St-co-EGDMA） particles was dependent on the crosslinker concentration and polymerization temperature.
基金financially supported by 973 Program of China,under the contract(No.2015CB655105)the National Science Fund for Distinguished Young Scholars(No.51225801)+1 种基金the National Natural Science Foundation of China(No.51408275)the Provincial Science and Technology Cooperation Project of Jiangsu-Guangxi cooperation project(No.BM2014050)
文摘The doubly thermo-responsive triblock copolymer nanoparticles of polystyrene-block-poly（N- isopropylacrylamide）-block-poly[N,N-（dimethylamino） ethyl methacrylate] （PS-b-PNIPAM-b-PDMAEMA） are successfully prepared through the seeded RAFT polymerization in situ by using the PS-b-PNIPAM-TTC diblock copolymer nanoparticles as the seed. The seeded RAFT polymerization undergoes a pseudo-first-order kinetics procedure, and the molecular weight increases with the monomer conversion linearly. The hydrodynamic diameter （Dh） of the triblock copolymer nanoparticles increases with the extension of the PDMAEMA block. In addition, the double thermo-response behavior of the PS-b-PNIPAM-b-PDMAEMA nanoparticles is detected by turbidity analysis, temperature-dependent 1H-NMR analysis, and DLS analysis. The seeded RAFT polymerization is believed as a valid method to prepare triblock copolymer nanoparticles containing two thermo-responsive blocks.
文摘In this study, P（St-MAA） seed latex particles were first prepared via soap-free emulsion polymerization of styrene （St） and methacrylic acid （MAA）, then the seed particles were allowed to swell with St at room temperature, and the P（St-MAA）/P（St- NaSS） core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate （NaSS） using AIBN as initiator in the presence of N,N^-methylenebisacrylamide （BAA, water-soluble crosslinker）. Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%, the narrow dispersed P（St-MAA） seed particles with the diameter of 150 nm and the P（St-MAA）/P（St-NaSS） core/shell latexes with the particle size of about 200 nm were synthesized. When the 25/75 mole ratio of NaSS/（St ＋ MAA） and 2 tool% of BAA were used in the seeded emulsion polymerization, the resulted P（St-MAA）/P（St-NaSS） latex product showed a low weight loss after water extraction, and the NaSS unit content in the whole particle and in the shell reached 11.7 mol% and 34.6 mol%, resoectivelv.
基金This work was supported by the National Natural Science Foundation of China
文摘The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solid content. The effects of monomer emulsion feed rates (R(a)) and (R/E)(E) values, the ratio of emulsifier amount between the initial charge (R) and the addition monomer emulsion (E), on the polymerization reaction features, the viscosities, surface tensions,particle sizes and particle sizes distributions of latexes, T-g and the insoluble fractions of films, the 180 degrees peel strength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, prepared from the latexes, were studied. Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180 degrees peel strength, tack and holding power.
基金financially supported by the National Natural Science Foundation of China(No.50943028)the Program for Liaoning Excellent Talents in Universities(No.LJQ2011037)
文摘Poly（methyl methacrylate）/poly（N-isopropylacrylamide） （PMMA/PNIPAM） core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide （NIPAM） in the presence of PMMA seed particles. The anionic potassium persulfate was used as initiator, and acrylic acid as functional comonomer. It was shown that the weight ratio of the PNIPAM shell to the PMMA core can be greatly increased through continuous addition of NIPAM monomer at a relatively slow rate. PMMA/PNIPAM particles with different shell thickness were obtained by varying the amount of charged NIPAM monomers. These particles exhibited unique nonspherical core-shell morphology. PMMA core was partially coated by dense hair-like or antler-like PNIPAM shell depending on the shell thickness. The measurement of these particles＇ zeta potential at different temperatures showed that the absolute value of zeta potential unusually decreased as the particle size decreased with temperature.
基金the second stage of BK21 program for supporting a fellowship
文摘A highly crosslinked, monodispersed polystyrene（PS） particle was prepared by a seeded batch dispersion polymerization with a monomer absorption method. Prior to polymerization, 1,9 lam monodispersed PS seed particles were treated under an optimum condition of monomer absorption. The effects of divinylbenzebe（DVB） concentration and polymerization temperature were examined for styrene（in PS seed）/styrene（in the second stage） mass ratio of 1：1 in the medium range of EtOH/water mass ratio of 100/0-80/20 and 2.3 μm uniform crosslinked PS particles containing 15%-20% （mass fraction） DVB were prepared at 60-70 ℃. The results show that monomer absorption before the second stage of polymerization is more effective to prepare highly crosslinked monodispersed PS particles.
文摘Microspheres based on binary polymer blend consisting of polystyrene (PSt), poly (methyl methacrylate) (PMMA), block copolymer comprising PSt and PMMA subunits, and ternary polymer blend consisting of PSt, PMMA, and block copolymer were fabricated by a solvent evaporation method, in which a polymer solution in dichloromethane was dispersed in water phase with the aid of a homogenizer to obtain an O/W emulsion followed by solvent evaporation with agitation to solidify the polymer. In the case of ternary blend, the effect of block copolymer content on the morphology of resulting spheres was investigated. Ternary blends afforded the bi-compartmental morphologies, the intermediate morphology between Janus and core-shell, which was confirmed by TEM observation. Seed polymerization of St or MMA was also carried out utilizing the resulting microspheres as seed particles in order to control the shape, and the surface morphology of particles. The particles with snowman-like morphology were obtained by seed polymerization of St using PSt/PMMA binary blend microspheres as seed particles. Surface roughness was controlled by the polymerization of MMA in the block copolymer seed, and that of St in the ternary blend seed.
基金supported by the Fundamental Research Funds for the Central Universities(No.BLX2013023)the National Natural Science Foundation of China(Nos.31271807 and 31501144)the Beijing Natural Science Foundation of China(No.6162020)
文摘Coating seeds with water absorbent materials can improve their survival, especially for those planted in drought or barren areas. In this study, effects of five kinds of super absorbent polymers(SAPs) on seed germination and seedling growth of Caragana korshinskii under drought conditions were investigated. Our results showed that SAP coatings could significantly improve the percentage and energy of seed germination, as well as reduce the relative electrical conductivity(REC), proline, malondialdehyde(MDA), H_2O_2 content, and peroxidase(POD) activity during germination. These results implied that seeds could uptake moisture from SAP coatings to alleviate drought-induced oxidative stress and membrane damage, thus exhibiting a better vigor and germination performance. After coating C. korshinskii seeds with SAPs, more seedlings emerged and grew better. Under the combined influence of the water absorption capacity of SAP and other factors, the efficiencies of five SAP coatings are in the sequence D>E>B>A>C. The function of the SAP coating on promoting seedling survival was confirmed in Mu Us Sandy Land in Ordos, Inner Mongolia Autonomous Region, China. The average seedling number of SAP D-coated seeds increased twofold on that of naked seeds. Our results are expected to be helpful in understanding and utilizing SAP seed coatings in improving plant survival under drought conditions.
文摘Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles formed at last. The shape was observed by SEM. These particles became ball-like when swollen by toluene, observed by optical microscope, and the release behavior of solvent from them was examined.
基金Supported by the research foundation by the U.S.Cotton Research and Promotion Program,U.S.Department of Agriculture and the Project of Combination of Industry,Education and Research of Ministry of Education of Guangdong Province,China(2011B090400358)
文摘The traditional method to refine crude cottonseed oil is time-consuming and expensive.This study evaluates the effectiveness of coagulation–flocculation–sedimentation process using quaternary polyamine-based polymers in refining crude cottonseed oil.Flocculated by four commercial polyamine-based cationic polymers(SL2700,SL3000,SL4500 and SL5000)with varied molecular weight(MW)and charge density(CD)and followed by coagulation with sodium hydroxide,crude cottonseed oil can be effectively purified.Free fatty acids,gossypol,pigments and trace elements are all effectively and sufficiently removed by the four polymers in a MW-and CDdependent manner.Our results suggest that the use of polyamine-based cationic polymers may offer an effective and feasible alternative to the traditional method for crude cottonseed oil refining.
文摘Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was swollen by toluene, and then the mixture of second monomers was added under polymerization condition. So a thin shell of poly(styrene-glycidyl methacrylate) cross-linked by triethylene glycol diacrylate was formed around the swollen PS particle. The bowl-shaped particles were obtained after the collapsing of the thin shell when the toluene emanated from the particles, but the shapes were effected by the degrees of cross-linking. The shape of the particles was observed by SEM. The release behavior of solvent from the particles was examined by TG.
文摘The objective of this work was to analyze the effects of the polymerization temperature on the kinetic features(instantaneous and overall conversions)and colloidal characteristics[mean particle diameter,stabilities]in the semicontinuous seeded cationic emulsion polymerization of styrene and butyl acrylate.Azobis is obutyl amidine hydrochloride was used as an initiator.The surfactants wascetyl trimethyl ammonium chloride.The results showed that the final instant when the polymerization temperature of 85℃emulsion highest conversion rate,and the temperature of the emulsion particle size,centrifugal stability is the best,85℃emulsion in the emulsion anti-dilution and acid salt stability also showed excellent stability.
基金supported by National Natural Science Foundation of China(No.50943028)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘A series of poly（2-acetoxyethyl methacrylate）/polystyrene（PAEMA/PS） latex interpenetrating polymer networks（LIPNs） were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator.These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase.The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.
基金financially supported by the National Basic Research Program of China(No.2014CB932202)
文摘Crosslinked x-P（St-MAA） seed latex was first prepared via soap-free emulsion copolymerization of styrene （St） and methyl methacrylic acid （MAA） with divinyl benzene as crosslinker and ammonium persulfate as initiator, and x-P（St-MAA）/x-P（St-NaSS） core/shell latex particles were then synthesized through a novel seeded emulsion copolymerization of St and sodium styrene sulphonate （NaSS） in the presence of water-soluble crosslinker N,N＇-methylene bisacrylamide （BAA） using oil-soluble 2,2-azobis isobutyronitrile as initiator. TEM observation indicated that narrow dispersed core/shell latex particles were obtained, and element analysis showed that NaSS unit content in the whole particle and in the shell reached 22.8 wt% and 51.2 wt%, respectively.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1F1A1067763).
文摘Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerization still constitutes a challenge.Herein,the kinetically controlled supramolecular polymerization of porphyrin derivatives was achieved in aqueous media by a seeding method based on a metastable state generated by synergistic metalation and Lewis acid–base complexation.
