Free volume theory was applied to the diffusion mechanism of drug through semi crystalline ethylene vinyl acetate (EVA) copolymer. According to free volume theory, drug diffused through semi crystalline EVA via vinyl ...Free volume theory was applied to the diffusion mechanism of drug through semi crystalline ethylene vinyl acetate (EVA) copolymer. According to free volume theory, drug diffused through semi crystalline EVA via vinyl acetate segments of the copolymer, and the dependence of D (D: diffusion coefficient of drug through EVA) on a (a :vinyl acetate content of copolymer; a <0.5) could be described as ln (D)=A1-A2/a(A1, A 2:constant). This was demonstrated by experimental data from several references.展开更多
The platelet adhesion and protein(Fibrinogen and albumin) adsorption ontoamphiphilic polystyrene-graft-poly(ethylene oxide) (PS-g-PEO) and polystyrene-graft -ω-stearyl-poly(ethyleneoxide) (PS-G-SPEO) were investigate...The platelet adhesion and protein(Fibrinogen and albumin) adsorption ontoamphiphilic polystyrene-graft-poly(ethylene oxide) (PS-g-PEO) and polystyrene-graft -ω-stearyl-poly(ethyleneoxide) (PS-G-SPEO) were investigated. It was found that the plateletadhesion on PS-g-SPEO was lower than that on PS-g-PEO. The PS-g-SPEO surface shows apreference for Albumin, while the PS-g-PEO surface absorbed Fibrinogen selectivelyu. Twoeffects of stearyl end group on PS-g-SPEO surface: (1) the lower surface free energe leadsto SPEO enrich at surface; (2) the stearyl end group absorbed albumin selectively, seems tocontribute to resistant the platelet adhesion. So the polymer surface modificed by both stearylgroup and poly(ethylene oxide) chain may be a new ideal way to improve material’s bloodcompatibility.展开更多
The polymerization of styrene was initiated by calixarene neodymium/di n butylmagnesium/hexamethylphosphoramide catalyst system. The average viscosity molecular weight of polystyrene increases as the concentration of ...The polymerization of styrene was initiated by calixarene neodymium/di n butylmagnesium/hexamethylphosphoramide catalyst system. The average viscosity molecular weight of polystyrene increases as the concentration of di n butylmagnesium or the Mg/Al molar ratio in the di n butylmagnesium increases. This result was explained by the state of association of butylmagnesium. As the state of association of di n butylmagnesium increases, the average viscosity molecular weight of polystyrene increases. [WT5HZ]展开更多
文摘Free volume theory was applied to the diffusion mechanism of drug through semi crystalline ethylene vinyl acetate (EVA) copolymer. According to free volume theory, drug diffused through semi crystalline EVA via vinyl acetate segments of the copolymer, and the dependence of D (D: diffusion coefficient of drug through EVA) on a (a :vinyl acetate content of copolymer; a <0.5) could be described as ln (D)=A1-A2/a(A1, A 2:constant). This was demonstrated by experimental data from several references.
文摘The platelet adhesion and protein(Fibrinogen and albumin) adsorption ontoamphiphilic polystyrene-graft-poly(ethylene oxide) (PS-g-PEO) and polystyrene-graft -ω-stearyl-poly(ethyleneoxide) (PS-G-SPEO) were investigated. It was found that the plateletadhesion on PS-g-SPEO was lower than that on PS-g-PEO. The PS-g-SPEO surface shows apreference for Albumin, while the PS-g-PEO surface absorbed Fibrinogen selectivelyu. Twoeffects of stearyl end group on PS-g-SPEO surface: (1) the lower surface free energe leadsto SPEO enrich at surface; (2) the stearyl end group absorbed albumin selectively, seems tocontribute to resistant the platelet adhesion. So the polymer surface modificed by both stearylgroup and poly(ethylene oxide) chain may be a new ideal way to improve material’s bloodcompatibility.
文摘The polymerization of styrene was initiated by calixarene neodymium/di n butylmagnesium/hexamethylphosphoramide catalyst system. The average viscosity molecular weight of polystyrene increases as the concentration of di n butylmagnesium or the Mg/Al molar ratio in the di n butylmagnesium increases. This result was explained by the state of association of butylmagnesium. As the state of association of di n butylmagnesium increases, the average viscosity molecular weight of polystyrene increases. [WT5HZ]
