Poly(vinyl alcohol)(PVA)is usually processed and used in a form of aqueous dispersion.A large number of inter-and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for proces...Poly(vinyl alcohol)(PVA)is usually processed and used in a form of aqueous dispersion.A large number of inter-and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for processing.In this study,carbon particles with different topological shapes were added into PVA aqueous dispersion to tune the steady and dynamic rheological behavior.The results show that the zero-dimensional particles(carbon black,CB)increase monotonically the zero-shear viscosity of PVA dispersion,while the one-dimensional particles(carbon nanotubes,CNTs)make it first increase,and then decrease and rise again,like an N-shape,and the two-dimensional particles(graphene oxide,GO)can make it first decrease and then increase,exhibiting a U-shape.It is believed that the topological shape of the carbon particles brought about these discrepancies.The zero-dimensional particles mainly act as physical crosslinking points due to their small size.While at a certain content,both CNTs and GO can destroy the intermolecular hydrogen bonds between PVA chains because the PVA chains can twine around the slim CNTs and the large planar size of GO prevents the adsorbed PVA from forming hydrogen bond with other chains.The high hydroxyl value of carbon particle surface could strengthen this effect.It is expected that the viscosity of polymer dispersion can be regulated by particles with different topological shape and the surface characteristic,so as to widen the operable concentration range during preparing composite functional materials.展开更多
This short review is dedicated to celebrate Prof.Shoukuan Fu’s 80 th birthday by discussing several of my accomplished projects over the past twenty years,which all applied radical polymerization in aqueous dispersed...This short review is dedicated to celebrate Prof.Shoukuan Fu’s 80 th birthday by discussing several of my accomplished projects over the past twenty years,which all applied radical polymerization in aqueous dispersed media for producing polymers with branched structures.These projects include the use of microemulsion polymerization for syntheses of fluorescent nanoparticles,hairy nanoparticles and hyperbranched polymers;the use of miniemulsion polymerization for synthesis of star polymers and light-emitting nanoparticles;the use of seeded emulsion polymerization for synthesis of hairy nanoparticles and hyperstar polymers;and the use of precipitation polymerization for synthesis of hollow polymer nanocapsules.Discussion of these projects demonstrates intriguing features of polymerization in biphasic dispersed media via either conventional radical polymerization or controlled radical polymerization to effectively regulate the branched structure of functional polymers.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51873180,52173024 and 51673172)Zhejiang Provincial Natural Science Foundation of China(No.LGF20B040001)。
文摘Poly(vinyl alcohol)(PVA)is usually processed and used in a form of aqueous dispersion.A large number of inter-and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for processing.In this study,carbon particles with different topological shapes were added into PVA aqueous dispersion to tune the steady and dynamic rheological behavior.The results show that the zero-dimensional particles(carbon black,CB)increase monotonically the zero-shear viscosity of PVA dispersion,while the one-dimensional particles(carbon nanotubes,CNTs)make it first increase,and then decrease and rise again,like an N-shape,and the two-dimensional particles(graphene oxide,GO)can make it first decrease and then increase,exhibiting a U-shape.It is believed that the topological shape of the carbon particles brought about these discrepancies.The zero-dimensional particles mainly act as physical crosslinking points due to their small size.While at a certain content,both CNTs and GO can destroy the intermolecular hydrogen bonds between PVA chains because the PVA chains can twine around the slim CNTs and the large planar size of GO prevents the adsorbed PVA from forming hydrogen bond with other chains.The high hydroxyl value of carbon particle surface could strengthen this effect.It is expected that the viscosity of polymer dispersion can be regulated by particles with different topological shape and the surface characteristic,so as to widen the operable concentration range during preparing composite functional materials.
基金the University of Notre Dame for financial support
文摘This short review is dedicated to celebrate Prof.Shoukuan Fu’s 80 th birthday by discussing several of my accomplished projects over the past twenty years,which all applied radical polymerization in aqueous dispersed media for producing polymers with branched structures.These projects include the use of microemulsion polymerization for syntheses of fluorescent nanoparticles,hairy nanoparticles and hyperbranched polymers;the use of miniemulsion polymerization for synthesis of star polymers and light-emitting nanoparticles;the use of seeded emulsion polymerization for synthesis of hairy nanoparticles and hyperstar polymers;and the use of precipitation polymerization for synthesis of hollow polymer nanocapsules.Discussion of these projects demonstrates intriguing features of polymerization in biphasic dispersed media via either conventional radical polymerization or controlled radical polymerization to effectively regulate the branched structure of functional polymers.
