The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measu...The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measured d n /d c of the solution decreases regularly and smoothly with increasing temperature until to the specific coil globule transition temperature of PNIPAM (around 32 ℃) and afterwards it increases with increasing temperature on the contrary. This extraordinary phenomenon is successfully explained and treated by a quantitative theory in terms of accompanying solvation desolvation process in the course of coil globule transition of the polymer chain in solution.展开更多
Aqueous solution properties of dendrimer PPI[Poly(propylene imine)] were studied by measuring viscosity parameters. Particularly on the extremely dilute concentration region were focused on. The adsorption constant k ...Aqueous solution properties of dendrimer PPI[Poly(propylene imine)] were studied by measuring viscosity parameters. Particularly on the extremely dilute concentration region were focused on. The adsorption constant k , critical concentration c a, intrinsic viscosity[ η ], intermolecular association constant K m and hydrodynamic contact concentration c s were calculated. And the generation number dependence of these parameters were also studied. From the results, the unique behavior of dendrimer solution was explained preliminary. The adsorption phenomenon of polymer solution is general, and the adsorption theory is also fit for dendrimers. Furthermore, the dynamic contact concentration c s was determined by a simple viscosity method for the first time.展开更多
The "single chain" microgels were synthesized successfully from the crosslinkable Poly( N isopropylacrylamide) copolymers. The viscosity properties show that the microgels have an even higher LCST than that ...The "single chain" microgels were synthesized successfully from the crosslinkable Poly( N isopropylacrylamide) copolymers. The viscosity properties show that the microgels have an even higher LCST than that of the corresponding linear copolymers.展开更多
The solid state morphology of the tri block copolymer PS b PCEMA b PtBA, which was synthesized by anionic polymerization with narrow molecular weight distribution, was in lamella structure from TEM micrographs. After ...The solid state morphology of the tri block copolymer PS b PCEMA b PtBA, which was synthesized by anionic polymerization with narrow molecular weight distribution, was in lamella structure from TEM micrographs. After being blended with polystyrene with the mass ratio of 1∶0 4, the morphology showed cylinder structure. With PS as continous phase, PCEMA and PtBA phases formed cylinders with PCEMA as outer layer. The nanofibres can be got and dispersed in good solvents of PS when the PCEMA phase was crosslinked. The t butyl group in PtBA phase can be cleavaged by reacting with TMSI, and nanofibres changed to nanotubes finally. It has the great potential applications, such as in the preparation of nanowires, template polymerization, nano reactor etc ..展开更多
文摘The temperature dependence of the specific refractive index increment d n /d c of aqueous poly( N isopropylacrylamide) solution in the range of 20 ℃ to 35 ℃ were determined by a differential refractometer. The measured d n /d c of the solution decreases regularly and smoothly with increasing temperature until to the specific coil globule transition temperature of PNIPAM (around 32 ℃) and afterwards it increases with increasing temperature on the contrary. This extraordinary phenomenon is successfully explained and treated by a quantitative theory in terms of accompanying solvation desolvation process in the course of coil globule transition of the polymer chain in solution.
文摘Aqueous solution properties of dendrimer PPI[Poly(propylene imine)] were studied by measuring viscosity parameters. Particularly on the extremely dilute concentration region were focused on. The adsorption constant k , critical concentration c a, intrinsic viscosity[ η ], intermolecular association constant K m and hydrodynamic contact concentration c s were calculated. And the generation number dependence of these parameters were also studied. From the results, the unique behavior of dendrimer solution was explained preliminary. The adsorption phenomenon of polymer solution is general, and the adsorption theory is also fit for dendrimers. Furthermore, the dynamic contact concentration c s was determined by a simple viscosity method for the first time.
文摘The "single chain" microgels were synthesized successfully from the crosslinkable Poly( N isopropylacrylamide) copolymers. The viscosity properties show that the microgels have an even higher LCST than that of the corresponding linear copolymers.
文摘The solid state morphology of the tri block copolymer PS b PCEMA b PtBA, which was synthesized by anionic polymerization with narrow molecular weight distribution, was in lamella structure from TEM micrographs. After being blended with polystyrene with the mass ratio of 1∶0 4, the morphology showed cylinder structure. With PS as continous phase, PCEMA and PtBA phases formed cylinders with PCEMA as outer layer. The nanofibres can be got and dispersed in good solvents of PS when the PCEMA phase was crosslinked. The t butyl group in PtBA phase can be cleavaged by reacting with TMSI, and nanofibres changed to nanotubes finally. It has the great potential applications, such as in the preparation of nanowires, template polymerization, nano reactor etc ..
