单电子转移活性自由基聚合法制备两亲星形聚丙烯酰胺

Synthesis of amphiphilic star-shaped polyacrylamide by single electron transfer living radical polymerization

以季戊四醇为原料,合成了星形大分子引发剂2-溴异丁酸季戊四醇四酯(PT-Br),并以此为四官能度引发剂,以CuBr/三-(2-二甲氨基乙基)胺(Me_6-TREN)原位歧化得到的初生零价铜(Cu^0)及二价铜与配体的络合物(Cu~ⅡX_2/L)为催化体系,室温下(18℃)在水溶液中实现了N-叔丁基丙烯酰胺(NtBA)和丙烯酰胺(AM)的单电子转移活性自由基共聚合(SET-LRP)。通过~1 H NMR和FTIR分析表明,所得聚合物为星形结构并且聚合物的链端保留了—Br端基。考察了各因素对聚合反应的影响,确定了聚合反应的最佳工艺条件为V(H_2O)=5mL,c(AM+NtBA)=4mol/L[x(NtBA)=4.1%],c(PT-Br)=0.004 3mol/L,c(CuBr)=0.008 9mol/L,V(Me_6-TREN)=13μL,反应时间8min,在室温(18℃)下制备出了黏均相对分子质量最大为6.94万的四臂星形P(AM-co-NtBA)。

The star-shaped P（AM-co-NtBA）was synthesized by single electron transfer living radical polymerization（SET-LRP）at room temperature（18 ℃）with H2 O as the solvent,pentaerythritol tetrakis（2-bromopropionate）（PT-Br）as the multifunctional initiator.Full disproportionation of CuBr/Me6 TREN to Cu（0）powder and CuBr2 in water prior to addition of both monomer and initiator is exploited to yield well-defined polyacrylamide.The polymer prepared via SET-LRP was characterized by 1 H NMR and FTIR to identify the polymerization mechanism,and the results show that polymer has the perfect functional chain ends（-Br）.The effects of reaction time,initiator dosage,CuBr dosage,monomer concentration and monomer ratio on the polymerization were investigated.The results show that the optimum process conditions for the polymerization ：deionized water is 5 mL,the concentration of monomer is 4 mol/L（NtBA 4.1%）,the concentration of initiator is 0.004 3 mol/L,the concentration of CuBr is 0.008 9 mol/L,The ligand is 13μL,the reaction temperature is 18℃（room temperature）,the reaction time is 8 min,the maximum molecular weight of the star-shaped P（AM-co-NtBA）can reach up to 69.4 thousand.