The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chrom...The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.展开更多
基金finanically supported by the National Natural Science Foundation of China (No. 21474010)the Priority Academic Program Development of Jiangsu Province
文摘The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.
