The dynamics of a series of poly(n-alkyl methacrylates) is investigated by means of ^(13)C spin-lattice relaxation experiments. The results show that the dynamics has the polymer property dependence.
Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl...Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.展开更多
To functionalize poly（vinyl chloride）（PVC） for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization（ATRP） initiated by the labile chlo...To functionalize poly（vinyl chloride）（PVC） for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization（ATRP） initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation（NIPS） process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA%（i.e., the PDMA weight percentage in copolymer） is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m·^-2·h^-1（0.5 MPa） and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.展开更多
A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis...A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.展开更多
Poly N-isopropyl acrylamide (abbreviated as PNIPA) as a kind of thermally sensitive hydrogel is utilized to concentrate Bovin Serum Albumin (BSA) solution. In order to decrease its surface adsorption to BSA in aqueous...Poly N-isopropyl acrylamide (abbreviated as PNIPA) as a kind of thermally sensitive hydrogel is utilized to concentrate Bovin Serum Albumin (BSA) solution. In order to decrease its surface adsorption to BSA in aqueous solution, surface layer grafting of the gels by radiation technology was carried out. The results showed that hydroxyl propyl methacrylate (HPMA) grained gel exhibited a low level of BSA adsorption and still kept the original thermally sensitive properties of PNIPA hydrogels.展开更多
A cup shape is a dynamic morphology of cells and organelles. With the aim of elucidating the formation of the biotic cup-shaped morphology, this study investigated cup-shaped vesicles consisting of an amphiphilic dibl...A cup shape is a dynamic morphology of cells and organelles. With the aim of elucidating the formation of the biotic cup-shaped morphology, this study investigated cup-shaped vesicles consisting of an amphiphilic diblock copolymer from the aspect of synthetic polymer chemistry. Cup-shaped vesicles were obtained by the polymerization-induced self-assembly of poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-methacrylic acid), PMAA-b-P(BMA-r-MAA), in an aqueous methanol solution using the photo nitroxide-mediated controlled/living radical polymerization technique. Field emission scanning electron microscopic observations demonstrated that the cup-shaped vesicles were suddenly formed during the late stage of the polymerization due to the extension of the hydrophobic P(BMA-r-MAA) block chain. During the early stage, the polymerization produced spherical vesicles rather than a cup shape. As the hydrophobic block chain was extended by the polymerization progress, the spherical vesicles reduced the size and were accompanied by the generation of small particles that were attached to the vesicles. The vesicles continued to reduce the size due to further extension of the hydrophobic chain;however, they suddenly grew into cup-shaped vesicles. This growth was accounted for by a change in the critical packing shape of the copolymer due to the hydrophobic chain extension. These findings are helpful for a better understanding of the biotic cup-shaped vesicle formation.展开更多
In this work, copolymerization of two functional monomers, glycidyl methacrylate （GMA） and N,N-dimethylaminoethyl methacrylate （DMAEMA）, was firstly carried out via reversible addition-fragmentation chain transfer...In this work, copolymerization of two functional monomers, glycidyl methacrylate （GMA） and N,N-dimethylaminoethyl methacrylate （DMAEMA）, was firstly carried out via reversible addition-fragmentation chain transfer （RAFT） polymerization successfully. The copolymerization kinetics was investigated under the molar ratio of n[GMA＋DMAEMA]o/n[AIBN]o/n[CPDN]o=300/1/3 at 60℃. The copolymerization showed typical ＂living＂ features such as first-order polymerization kinetics, linear increase of molecular weight with monomer conversion and narrow molecular weight distribution. The reactivity ratios of GMA and DMAEMA were calculated by the extended Kelen-Tudos linearization methods. The epoxy group of the copolymer PGMA-co-PDMAEMA remained intact under the conditions of RAFT copolymerization and could easily be post-modified by ethylenedia- mine. Moreover, the modified copolymer could be used as a gene carrier.展开更多
基金Supported by The National Natural Science Foundation of China
文摘The dynamics of a series of poly(n-alkyl methacrylates) is investigated by means of ^(13)C spin-lattice relaxation experiments. The results show that the dynamics has the polymer property dependence.
文摘Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.
基金financially supported by the National 863 Program(No.2012AA03A602)National 973 Program(No.2009CB623402)the National Natural Science Foundation of China(No.U1134002)
文摘To functionalize poly（vinyl chloride）（PVC） for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization（ATRP） initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation（NIPS） process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA%（i.e., the PDMA weight percentage in copolymer） is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m·^-2·h^-1（0.5 MPa） and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.
文摘A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.
基金This project is sponsored by the National Natural Science Foundation of China.
文摘Poly N-isopropyl acrylamide (abbreviated as PNIPA) as a kind of thermally sensitive hydrogel is utilized to concentrate Bovin Serum Albumin (BSA) solution. In order to decrease its surface adsorption to BSA in aqueous solution, surface layer grafting of the gels by radiation technology was carried out. The results showed that hydroxyl propyl methacrylate (HPMA) grained gel exhibited a low level of BSA adsorption and still kept the original thermally sensitive properties of PNIPA hydrogels.
文摘A cup shape is a dynamic morphology of cells and organelles. With the aim of elucidating the formation of the biotic cup-shaped morphology, this study investigated cup-shaped vesicles consisting of an amphiphilic diblock copolymer from the aspect of synthetic polymer chemistry. Cup-shaped vesicles were obtained by the polymerization-induced self-assembly of poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-methacrylic acid), PMAA-b-P(BMA-r-MAA), in an aqueous methanol solution using the photo nitroxide-mediated controlled/living radical polymerization technique. Field emission scanning electron microscopic observations demonstrated that the cup-shaped vesicles were suddenly formed during the late stage of the polymerization due to the extension of the hydrophobic P(BMA-r-MAA) block chain. During the early stage, the polymerization produced spherical vesicles rather than a cup shape. As the hydrophobic block chain was extended by the polymerization progress, the spherical vesicles reduced the size and were accompanied by the generation of small particles that were attached to the vesicles. The vesicles continued to reduce the size due to further extension of the hydrophobic chain;however, they suddenly grew into cup-shaped vesicles. This growth was accounted for by a change in the critical packing shape of the copolymer due to the hydrophobic chain extension. These findings are helpful for a better understanding of the biotic cup-shaped vesicle formation.
文摘In this work, copolymerization of two functional monomers, glycidyl methacrylate （GMA） and N,N-dimethylaminoethyl methacrylate （DMAEMA）, was firstly carried out via reversible addition-fragmentation chain transfer （RAFT） polymerization successfully. The copolymerization kinetics was investigated under the molar ratio of n[GMA＋DMAEMA]o/n[AIBN]o/n[CPDN]o=300/1/3 at 60℃. The copolymerization showed typical ＂living＂ features such as first-order polymerization kinetics, linear increase of molecular weight with monomer conversion and narrow molecular weight distribution. The reactivity ratios of GMA and DMAEMA were calculated by the extended Kelen-Tudos linearization methods. The epoxy group of the copolymer PGMA-co-PDMAEMA remained intact under the conditions of RAFT copolymerization and could easily be post-modified by ethylenedia- mine. Moreover, the modified copolymer could be used as a gene carrier.
