Dynamic mechanical analysis was used to study the mechanical properties and microstructureof crazes in polystyrene produced in air or in methanol at different temperatures. A new loss peakwas found at about 82℃,which...Dynamic mechanical analysis was used to study the mechanical properties and microstructureof crazes in polystyrene produced in air or in methanol at different temperatures. A new loss peakwas found at about 82℃,which is assigned to glass transition peak of craze fibrils. The decreaseof glass transition temperature of polymer in craze fibrils is due to the high values of surface tovolume ratio. The glass transition temperature ratio of craze fibrils to bulk material （T;/Tg） hasbeen expressed as a function of the fibrils diameter （d）. From T;of craze fibrils,the value of fibrildiameter can be calculated. Annealing the crazed specimen at room temperature makes the fibrilsplastically deform and cause the fibrils to thin slightly,whereas annealing the crazed specimen atthe temperature near T;of the craze fibrils makes the fibrils bundle together.展开更多
The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild condit...The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild conditions to form bis (benzotriazolato) copper (Ⅱ) and benzotriazolato copper (Ⅰ)which covered the surface of copper metal in the shape of polymeric materials. Since benzotriazole is of great interest as a ligand in that its presence in many biological system with metal ions, and is considered as a corrosion inhibitor, this work will be in favour of the study of protective corrosion.展开更多
Silver surfaces producing enhancement of the Raman scattering for adsorbed molecules have been simply prepared by etching them in HNO<sub>3</sub> solution. The dependence of the enhancement on etching time...Silver surfaces producing enhancement of the Raman scattering for adsorbed molecules have been simply prepared by etching them in HNO<sub>3</sub> solution. The dependence of the enhancement on etching time at different concentrations of the etching solution has also been investigated. When etched with 2.5 mol/L HNO<sub>3</sub> for 10-20 min, silver surfaces can all produce strong enhancement, and the surface-enhanced Raman scattering （SERS） activity can survive for more than 10 h in air. For Kr<sup>+</sup> laser excitation at 647.1 nm, the observed展开更多
文摘Dynamic mechanical analysis was used to study the mechanical properties and microstructureof crazes in polystyrene produced in air or in methanol at different temperatures. A new loss peakwas found at about 82℃,which is assigned to glass transition peak of craze fibrils. The decreaseof glass transition temperature of polymer in craze fibrils is due to the high values of surface tovolume ratio. The glass transition temperature ratio of craze fibrils to bulk material （T;/Tg） hasbeen expressed as a function of the fibrils diameter （d）. From T;of craze fibrils,the value of fibrildiameter can be calculated. Annealing the crazed specimen at room temperature makes the fibrilsplastically deform and cause the fibrils to thin slightly,whereas annealing the crazed specimen atthe temperature near T;of the craze fibrils makes the fibrils bundle together.
文摘The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild conditions to form bis (benzotriazolato) copper (Ⅱ) and benzotriazolato copper (Ⅰ)which covered the surface of copper metal in the shape of polymeric materials. Since benzotriazole is of great interest as a ligand in that its presence in many biological system with metal ions, and is considered as a corrosion inhibitor, this work will be in favour of the study of protective corrosion.
文摘Silver surfaces producing enhancement of the Raman scattering for adsorbed molecules have been simply prepared by etching them in HNO<sub>3</sub> solution. The dependence of the enhancement on etching time at different concentrations of the etching solution has also been investigated. When etched with 2.5 mol/L HNO<sub>3</sub> for 10-20 min, silver surfaces can all produce strong enhancement, and the surface-enhanced Raman scattering （SERS） activity can survive for more than 10 h in air. For Kr<sup>+</sup> laser excitation at 647.1 nm, the observed
