An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br...An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br and N,N,N’,N″,N-pentamethyldiethylenetriamine(PMDETA).Azidation of the terminal bromine was followed in DMF with sodium azide,and α-azide,ω-alkyne PMMA precursor was obtained.Then the “click” cylcization of precursor between terminal azide and alkyne was carried out under the catalysis of CuBr/PMDETA,during the course of the reaction,a pseudo-high dilution technique was utilized to ensure the favored intramolecular cylcization.The nearly complete cylcization has been confirmed by a combination of IR,1H NMR and GPC analysis,and cyclo-PMMA with an Mn of 15000,PDI of 1.38 was obtained.展开更多
A novel hydroxy-capped comb-like block polymer, poly[poly(ethylene glycol)](HCPEG), was prepared via atom transfer radical polymerization(ATRP) of α-methylacryloyl-ω-hydroxyl-poly(ethylene glycol). The polymerizatio...A novel hydroxy-capped comb-like block polymer, poly[poly(ethylene glycol)](HCPEG), was prepared via atom transfer radical polymerization(ATRP) of α-methylacryloyl-ω-hydroxyl-poly(ethylene glycol). The polymerization kinetics of the PHPEGMA was studied by gel permeation chromatography and 1H NMR. The semilogarithmic plot of monomer conversion vs. reaction time increases linearly before the conversion is up to more than 70% and the number-average molecular weights(M_n) by GPC increased linearly with increase of the monomer conversion up to 100%, while the polydispersity index remained fairly narrow with M_w/M_n<1.2.展开更多
A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated poly...A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated polystyrene(PSt-Br)4 was obtained from ATRP of styrene using pentaerythritol tetra(2-bromoisobutyrate) as an initiator,and the(PSt-Br)4 was efficiently converted to the azido-terminated polymers[(PSt-N3)4] through the bromine substitution reaction with sodium azide.Furthermore,the(PSt-N3)4 reacted with propargyl 2,2-bis[2-(bromomethyl)propionato]propionyrate via a click reaction,1,3-dipolar cycloaddition reaction,and the polymer[(PSt-Br2)4] containing eight end-bromine was obtained.The(PSt-Br2)4 could further serve as a macroinitiator for the ATRP of methyl methacrylate(MMA).Accordingly,the dendrimer-like star polymer,[(PMMA)2PSt]4 was successfully prepared.The structure of [(PMMA)2PSt]4 was characterized via IR,1H NMR,GPC and DSC.展开更多
采用原子转移自由基聚合(ATRP)法聚合甲基烯丙基聚氧乙烯醚(HPEG)和丙烯酸甲酯(PMA),生成低分子量梳形结构的低聚物HPEG/PMA.经Fourier红外光谱(FT-IR)和核磁共振氢谱(1 H NMR)对其结构特征基团进行分析,确认合成了目标产物.对HPEG/PMA...采用原子转移自由基聚合(ATRP)法聚合甲基烯丙基聚氧乙烯醚(HPEG)和丙烯酸甲酯(PMA),生成低分子量梳形结构的低聚物HPEG/PMA.经Fourier红外光谱(FT-IR)和核磁共振氢谱(1 H NMR)对其结构特征基团进行分析,确认合成了目标产物.对HPEG/PMA进行凝胶渗透色谱(GPC)测试,结果表明,ATRP法制备的梳形HPEG/PMA分子量为7.7×103,分布系数为1.11,具有优异的可控性.梳形HPEG/PMA经V(乙醇)∶V(水)=1的NaOH溶液水解,得到梳形结构甲基烯丙基聚氧乙烯醚和丙烯酸(HPEG/PAA)低聚物.展开更多
文摘An efficient route to macrocyclic polymers via “click” cyclization was presented.The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique,initiated with propargyl 2-bromoisobutyrate,Cu(Ⅰ)Br and N,N,N’,N″,N-pentamethyldiethylenetriamine(PMDETA).Azidation of the terminal bromine was followed in DMF with sodium azide,and α-azide,ω-alkyne PMMA precursor was obtained.Then the “click” cylcization of precursor between terminal azide and alkyne was carried out under the catalysis of CuBr/PMDETA,during the course of the reaction,a pseudo-high dilution technique was utilized to ensure the favored intramolecular cylcization.The nearly complete cylcization has been confirmed by a combination of IR,1H NMR and GPC analysis,and cyclo-PMMA with an Mn of 15000,PDI of 1.38 was obtained.
文摘A novel hydroxy-capped comb-like block polymer, poly[poly(ethylene glycol)](HCPEG), was prepared via atom transfer radical polymerization(ATRP) of α-methylacryloyl-ω-hydroxyl-poly(ethylene glycol). The polymerization kinetics of the PHPEGMA was studied by gel permeation chromatography and 1H NMR. The semilogarithmic plot of monomer conversion vs. reaction time increases linearly before the conversion is up to more than 70% and the number-average molecular weights(M_n) by GPC increased linearly with increase of the monomer conversion up to 100%, while the polydispersity index remained fairly narrow with M_w/M_n<1.2.
文摘A new approach to the synthesis of dendrimer-like star polymer,[(PMMA)2PSt]4,was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry.Firstly four-arm bromine-terminated polystyrene(PSt-Br)4 was obtained from ATRP of styrene using pentaerythritol tetra(2-bromoisobutyrate) as an initiator,and the(PSt-Br)4 was efficiently converted to the azido-terminated polymers[(PSt-N3)4] through the bromine substitution reaction with sodium azide.Furthermore,the(PSt-N3)4 reacted with propargyl 2,2-bis[2-(bromomethyl)propionato]propionyrate via a click reaction,1,3-dipolar cycloaddition reaction,and the polymer[(PSt-Br2)4] containing eight end-bromine was obtained.The(PSt-Br2)4 could further serve as a macroinitiator for the ATRP of methyl methacrylate(MMA).Accordingly,the dendrimer-like star polymer,[(PMMA)2PSt]4 was successfully prepared.The structure of [(PMMA)2PSt]4 was characterized via IR,1H NMR,GPC and DSC.
文摘采用原子转移自由基聚合(ATRP)法聚合甲基烯丙基聚氧乙烯醚(HPEG)和丙烯酸甲酯(PMA),生成低分子量梳形结构的低聚物HPEG/PMA.经Fourier红外光谱(FT-IR)和核磁共振氢谱(1 H NMR)对其结构特征基团进行分析,确认合成了目标产物.对HPEG/PMA进行凝胶渗透色谱(GPC)测试,结果表明,ATRP法制备的梳形HPEG/PMA分子量为7.7×103,分布系数为1.11,具有优异的可控性.梳形HPEG/PMA经V(乙醇)∶V(水)=1的NaOH溶液水解,得到梳形结构甲基烯丙基聚氧乙烯醚和丙烯酸(HPEG/PAA)低聚物.
