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以四丁基溴化铵(BNBr)或四丁基碘化铵(BNI)作为有机催化剂,碘(I_2)与偶氮二异丁腈(AIBN)原位生成烷基碘化物为引发剂在本体聚合中实现了甲基丙烯酸甲酯(MMA)的可逆催化络合聚合(RCMP).首先,比较了2种催化剂对该体系催化活性的大小,相同实验条件下,BNI作为催化剂时对聚合的控制效果优于BNBr,即在该体系中BNI的催化活性大于BNBr;其次,较为详细地研究了催化剂BNI的用量对MMA可控聚合的影响,结果表明,BNI的浓度在9.43~117.81 mmol/L范围内均有较好的控制效果,当[MMA]∶[I_2]∶[AIBN]∶[BNI]=100∶0.5∶0.75∶0.25,即催化剂的浓度为23.56 mmol/L时反应速率较快,理论分子量与实测分子量(通过GPC进行表征)几乎完全吻合,分子量多分散指数(PDI=M_w/M_n)较小(PDI<1.27);最后,通过1H-NMR对所得聚合物的结构进行表征,证明为碘原子封端,M_(n,NMR)与M_(n,GPC)相吻合,端基保有度达到98.8%.
Using BNBr or tetrabutylammonium iodide (BNI) as organic catalyst, iodine (I_2) and azobisisobutyronitrile (AIBN) were used to generate alkyl iodide as initiator in bulk In the polymerization, the reversible catalytic complex polymerization (RCMP) of methyl methacrylate (MMA) was realized.Firstly, the catalytic activity of the two catalysts was compared with that under the same experimental conditions, and the polymerization was controlled under the same experimental conditions Which is better than BNBr, that is, the catalytic activity of BNI in this system is greater than that of BNBr. Secondly, the influence of BNI dosage on the controlled polymerization of MMA was studied in detail. The results showed that BNI concentration ranged from 9.43 to 117.81 mmol / L (MMA): [I_2]: [AIBN]: [BNI] = 100: 0.5: 0.75: 0.25, ie the catalyst concentration is 23.56 mmol / L, the reaction rate is faster. The theoretical The molecular weight and the measured molecular weight (characterized by GPC) are nearly identical, and the polydispersity index (PDI = M_w / M_n) is small (PDI <1.27). Finally, the structure of the obtained polymer was characterized by 1H- The iodine atom was capped, M_ (n, NMR) was consistent with M_ (n, GPC), the end group retention reached 98.8%.