Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were...Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability for trapping an active superoxide anion radicals generated in the HX/XO system and the stability of their spin adduct of DEPPEPO were analyzed. In addition, the effects of 5 phenylethyl and 5 phenyl substituted analogues of DMPO on the stereochemistry of the corresponding spin adducts were systematically illustrated.展开更多
A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridin...A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.展开更多
A series of tri\|component copolyesters composed of glycolide/lactide/caprolactone (PGLC) were obtained by bulk ring\|opening copolymerization of glycolide(GA),L\|lactide (L\|LA) and caprolactone(CL) with Sn(Oct)\-2 a...A series of tri\|component copolyesters composed of glycolide/lactide/caprolactone (PGLC) were obtained by bulk ring\|opening copolymerization of glycolide(GA),L\|lactide (L\|LA) and caprolactone(CL) with Sn(Oct)\-2 as catalyst for the purpose of biomedical applications.Structure of the PGLC copolyester was characterized by means of GPC,\{\}\+1H\|NMR,DSC and X\|ray diffractometry techniques.It was found that the obtained polymer was a pure copolymer that consisting of no other side\|produced polymers and the copolyester was a random copolymer that presented an amorphous structure in a large range of composition.The hydrophilicity and degradation rate of the copolyester were also studied in detail and it was found that the hydrophilicity and hydrolysis rate were improved by increasing the amount of GA.The mechanical properties of the PGLC copolyester were identified by measuring the tensile strength and the elongation at break.The elongation of the copolyester could be improved by introducing CL to the PLGA.That the PGLC copolyester was a potential biomedical material was suggested.展开更多
A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium com...A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.展开更多
文摘Synthesis of a novel α phosphorus containing spin trap, DEPPEPO[5 (diethoxyphosphoryl) 5 phenylethyl 1 pyrroline] N oxide and evaluation of its ability to spin trap the hydroxyl and the superoxide anion radicals were described in the present article. The ability for trapping an active superoxide anion radicals generated in the HX/XO system and the stability of their spin adduct of DEPPEPO were analyzed. In addition, the effects of 5 phenylethyl and 5 phenyl substituted analogues of DMPO on the stereochemistry of the corresponding spin adducts were systematically illustrated.
文摘A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.
文摘A series of tri\|component copolyesters composed of glycolide/lactide/caprolactone (PGLC) were obtained by bulk ring\|opening copolymerization of glycolide(GA),L\|lactide (L\|LA) and caprolactone(CL) with Sn(Oct)\-2 as catalyst for the purpose of biomedical applications.Structure of the PGLC copolyester was characterized by means of GPC,\{\}\+1H\|NMR,DSC and X\|ray diffractometry techniques.It was found that the obtained polymer was a pure copolymer that consisting of no other side\|produced polymers and the copolyester was a random copolymer that presented an amorphous structure in a large range of composition.The hydrophilicity and degradation rate of the copolyester were also studied in detail and it was found that the hydrophilicity and hydrolysis rate were improved by increasing the amount of GA.The mechanical properties of the PGLC copolyester were identified by measuring the tensile strength and the elongation at break.The elongation of the copolyester could be improved by introducing CL to the PLGA.That the PGLC copolyester was a potential biomedical material was suggested.
文摘A rigid silica colloidal crystal template was formed by self assembly of the monodispersed silica dispersion prepared according to Stber method. Within the interstitial void of the template, β diketonate titanium complexes[(dbm) 3Ti(OPh)/MAO] catalyzed polymerization of styrene was carried out to form syndiotactic polystyrene(sPS)/silica composites. The titled ordered macroporous syndiotactic polystyrene was achieved by chemical decomposition of the silica template with concentrated aqueous hydrofluoric acid, which was confirmed by SEM results. FTIR spectra indicated that all silica was removed from the composites in this study. DSC revealed that the as prepared macroporous sPS was significantly different from the bulk one, and the unique properties were inherent rather than from the enforcement effect by the silica template. Further investigation concerning the inherent microstrucutures about the molecular weight and its distribution, tacticity of the styrene etc . and their dependence on the confinement is in progress.
