The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is dete...The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is determined from the absorbance change of bromophenol blue solution as function of copolymer concentration, which is about 1×10 -6 mol/L. The critical coagulation concentration (cz c) of electrolytes with different valence(z) for the copolymer micelles are examined by visual method and compared with that obtained by experiential formula cz c∝z -6. The relation formula for different cations is deduced:cz c∝z -4, which indicates the electronegative character of the micelle surface.展开更多
AIM: To compare same-day whole-dose vs split-dose of 2-litre polyethylene glycol electrolyte lavage solution (PEG-ELS) plus bisacodyl for colon cleansing for morning colonoscopy.
Polylactide was blended with starch and polyethylene to get a plastic with good processabllity, mechanical behavior, and biodegradability. The dispersion of starch, melt index, mechanical behavior and biodegradability...Polylactide was blended with starch and polyethylene to get a plastic with good processabllity, mechanical behavior, and biodegradability. The dispersion of starch, melt index, mechanical behavior and biodegradability of blends with various blending ratio were studied.展开更多
This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ ...This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ and above 0℃. The amount of catalyst used was studied. When zinc iodide catalyst used is more than 10mol% relative to monomer, the rate of polymerization is proportional to the concentration of monomer, whereas zinc iodide catalyst used is less than 10 mol% of the monomer, the rate of polymerization is independent of the monomer concentration.In the GTP of EA an induction period was observed when the zinc iodide contents are less than l0mol%. If the reaction temperature is over 0℃, living species become unstable and diminish, leading to incomplete monomer conversion. The reaction curves equations are obtained. The polymers have narrow molecular weight distributions which are not changed as decreasing zinc iodide contents. The polydispersity is about 1.2.展开更多
文摘The critical micelle concentration(CMC) value and surface charge of the amphiphilic graft copolymer PECA-g-PEG micelles(PECA:polyethyl cyanoacrylae, PEG:polyethylene glycol) are reported. CMC of the copolymers is determined from the absorbance change of bromophenol blue solution as function of copolymer concentration, which is about 1×10 -6 mol/L. The critical coagulation concentration (cz c) of electrolytes with different valence(z) for the copolymer micelles are examined by visual method and compared with that obtained by experiential formula cz c∝z -6. The relation formula for different cations is deduced:cz c∝z -4, which indicates the electronegative character of the micelle surface.
基金Supported by University of Malaya Research Grant,Project No.RG536-13HTM
文摘AIM: To compare same-day whole-dose vs split-dose of 2-litre polyethylene glycol electrolyte lavage solution (PEG-ELS) plus bisacodyl for colon cleansing for morning colonoscopy.
文摘Polylactide was blended with starch and polyethylene to get a plastic with good processabllity, mechanical behavior, and biodegradability. The dispersion of starch, melt index, mechanical behavior and biodegradability of blends with various blending ratio were studied.
文摘This paper reports the kinetics of group transfer polymerization (GTP)of ethyl acrylate (EA)with zinc iodide catalyst in 1,2-dichloroethane using dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator at 0℃ and above 0℃. The amount of catalyst used was studied. When zinc iodide catalyst used is more than 10mol% relative to monomer, the rate of polymerization is proportional to the concentration of monomer, whereas zinc iodide catalyst used is less than 10 mol% of the monomer, the rate of polymerization is independent of the monomer concentration.In the GTP of EA an induction period was observed when the zinc iodide contents are less than l0mol%. If the reaction temperature is over 0℃, living species become unstable and diminish, leading to incomplete monomer conversion. The reaction curves equations are obtained. The polymers have narrow molecular weight distributions which are not changed as decreasing zinc iodide contents. The polydispersity is about 1.2.
