Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation...Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.展开更多
A hydrophilic/hydrophobic interpenetrating polymer network （IPN） of poly （vinyl alcohol） / polystyrene was prepared by conversion of the IPN of poly （vinyl acetate）/polystyrene. The hydrophilic/hydrophobic IPN w...A hydrophilic/hydrophobic interpenetrating polymer network （IPN） of poly （vinyl alcohol） / polystyrene was prepared by conversion of the IPN of poly （vinyl acetate）/polystyrene. The hydrophilic/hydrophobic IPN was characterized by FT-IR and DSC, and the swelling ratios of the IPN in different solvents were measured.展开更多
Poly(vinyl alcohol)(PVA)has been widely used in industrial and consumer products.In this study,we aimed to address this challenge by synthesizing well-defined multiarm poly(vinyl acetate)(PVAc)through the use of nonhy...Poly(vinyl alcohol)(PVA)has been widely used in industrial and consumer products.In this study,we aimed to address this challenge by synthesizing well-defined multiarm poly(vinyl acetate)(PVAc)through the use of nonhydrolyzable vinyl ethertype multifunctional RAFT agents.The control over molecular weights was achieved by the RAFT process to afford polymers with dominant head-to-head linkages at the terminal.Especially,quantitative end-functionalization of the synthesized PVAc was performed using Michael thiol−ene or disulfide exchange reactions.Consequently,saponification of the PVAc enabled the synthesis of end-functionalized multiarm PVA in an efficient manner.This straightforward approach afforded well-defined functional PVAs,which enable further chemical modification,thus widening the utility of PVA in a range of applications,such as precisely controlled network synthesis and bioconjugation.展开更多
Polymer functionalization is a powerful tool to prepare polymers with diverse structures without the need of synthesizing monomers or performing polymerization reactions.Polymers that are difficult to be synthesized u...Polymer functionalization is a powerful tool to prepare polymers with diverse structures without the need of synthesizing monomers or performing polymerization reactions.Polymers that are difficult to be synthesized using direct polymerization reactions can be accessed using polymer functionalization.We herein present Mitsunobu derivatization of poly(vinyl alcohol)(PVA)to convert the hydroxyl groups into diverse functional groups.展开更多
Different weight percentage of ZnBr_(2) doped poly(vinyl alcohol)(PVA)free standing composite films were prepared using solution casting method.These films were characterized for analyzing structural,dielectric,electr...Different weight percentage of ZnBr_(2) doped poly(vinyl alcohol)(PVA)free standing composite films were prepared using solution casting method.These films were characterized for analyzing structural,dielectric,electrochemical properties.This paper mainly focused to understand the contribution of physical phenomenon on conductivity in terms of dielectric parameters.FTIR spectrum confirms the interaction between ZnBr_(2) and PVA.Pseudo-capacitive behavior observed from cyclic voltammograms.Dielectric properties of the composites follow non-Debye type behavior.The conducting phenomenon occurs due to hopping of ions between coordination sites present in the composite and the segmental relaxation of polymer chain.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 29873058).
文摘Stable and well-dispersed poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloidal clusters wereprepaxed via the reduction of ruthenium(III) chloride by refluxing with low boiling point alcohols. Investigation of the size ofRu colloids by transmission electron microscopy (TEM) indicated that the average diametes could be controlled in the rangeof 1.2-1.6 nm with relative standard deviations of less than 0.33 by changing the molar ratio of PVP to Ru. The X-rayphotoelectron spectroscopy (XPS) characterization verified the formation of elemental ruthenium colloids.
基金supported by the National Natural Science Foundation of China(No.20474015)the Scientific Research Fund of Hunan Provincial Education Department(No.04A029).
文摘A hydrophilic/hydrophobic interpenetrating polymer network （IPN） of poly （vinyl alcohol） / polystyrene was prepared by conversion of the IPN of poly （vinyl acetate）/polystyrene. The hydrophilic/hydrophobic IPN was characterized by FT-IR and DSC, and the swelling ratios of the IPN in different solvents were measured.
文摘Poly(vinyl alcohol)(PVA)has been widely used in industrial and consumer products.In this study,we aimed to address this challenge by synthesizing well-defined multiarm poly(vinyl acetate)(PVAc)through the use of nonhydrolyzable vinyl ethertype multifunctional RAFT agents.The control over molecular weights was achieved by the RAFT process to afford polymers with dominant head-to-head linkages at the terminal.Especially,quantitative end-functionalization of the synthesized PVAc was performed using Michael thiol−ene or disulfide exchange reactions.Consequently,saponification of the PVAc enabled the synthesis of end-functionalized multiarm PVA in an efficient manner.This straightforward approach afforded well-defined functional PVAs,which enable further chemical modification,thus widening the utility of PVA in a range of applications,such as precisely controlled network synthesis and bioconjugation.
基金This work was financially supported by the National Natural Science Foundation of China(22075292,22001254)。
文摘Polymer functionalization is a powerful tool to prepare polymers with diverse structures without the need of synthesizing monomers or performing polymerization reactions.Polymers that are difficult to be synthesized using direct polymerization reactions can be accessed using polymer functionalization.We herein present Mitsunobu derivatization of poly(vinyl alcohol)(PVA)to convert the hydroxyl groups into diverse functional groups.
基金Science and Engineering Research Board(SERB)Department of Science and Technology(DST),Government of India for the research projects(SR/FTP/PS-011/2010)and(SB/EMEQ-089/2013).
文摘Different weight percentage of ZnBr_(2) doped poly(vinyl alcohol)(PVA)free standing composite films were prepared using solution casting method.These films were characterized for analyzing structural,dielectric,electrochemical properties.This paper mainly focused to understand the contribution of physical phenomenon on conductivity in terms of dielectric parameters.FTIR spectrum confirms the interaction between ZnBr_(2) and PVA.Pseudo-capacitive behavior observed from cyclic voltammograms.Dielectric properties of the composites follow non-Debye type behavior.The conducting phenomenon occurs due to hopping of ions between coordination sites present in the composite and the segmental relaxation of polymer chain.
