Linear or cross linked aqueous polyurethane dispersions with carboxyl Ag salt were prepared. TEM photos show that Ag + was homogeneously distributed in the microspheres. The Ag + was reduced in situ by photochemical m...Linear or cross linked aqueous polyurethane dispersions with carboxyl Ag salt were prepared. TEM photos show that Ag + was homogeneously distributed in the microspheres. The Ag + was reduced in situ by photochemical method. For linear polyurethane particles, as the extent of the reduction reaction of silver ions increased, the silver particles grew larger, but the number of the silver particles kept almost constant. In crosslinked polymer system, the number of silver particles increased, but the size of silver particles remained almost the same. We concluded that nucleation and growth of the silver particle are the result of the silver atom movement in the polymer matrix. In the linear polymer system, the movement of silver atom and aggregation of silver particles result in the formation and growth of several silver particles; in the cross linked polymer system, the polymer chain prevents the movement of silver particles, resulting in a number increase of silver particles.展开更多
Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional...Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional initiator(THABI).The structures of the polymers obtained were characterized by 1H\|NMR and SEC/refractive index(RI)/right anagle laser light scattering(RALLS)/differential viscometer(DV).Molecular weight(MW),molecular weight distribution(MWD) and degree of branching(DB) were influenced by conversion and initial feed molar ratio of BPEA,MA and THABI.The addition of THABI can narrow the MWDs of the polymers obtained.The results are consistent with our simulation result.展开更多
文摘Linear or cross linked aqueous polyurethane dispersions with carboxyl Ag salt were prepared. TEM photos show that Ag + was homogeneously distributed in the microspheres. The Ag + was reduced in situ by photochemical method. For linear polyurethane particles, as the extent of the reduction reaction of silver ions increased, the silver particles grew larger, but the number of the silver particles kept almost constant. In crosslinked polymer system, the number of silver particles increased, but the size of silver particles remained almost the same. We concluded that nucleation and growth of the silver particle are the result of the silver atom movement in the polymer matrix. In the linear polymer system, the movement of silver atom and aggregation of silver particles result in the formation and growth of several silver particles; in the cross linked polymer system, the polymer chain prevents the movement of silver particles, resulting in a number increase of silver particles.
文摘Hyperbranched polyacrylate copolymers were synthesized by self\|condensing vinyl copolymerization (SCVCP) of 2\|[(2\|bromopropionyl)oxy]ethyl acrylate(BPEA) and methyl acrylate(MA) in the presence of a tetrafunctional initiator(THABI).The structures of the polymers obtained were characterized by 1H\|NMR and SEC/refractive index(RI)/right anagle laser light scattering(RALLS)/differential viscometer(DV).Molecular weight(MW),molecular weight distribution(MWD) and degree of branching(DB) were influenced by conversion and initial feed molar ratio of BPEA,MA and THABI.The addition of THABI can narrow the MWDs of the polymers obtained.The results are consistent with our simulation result.
