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Anionic polymerization of fluorine-substituted phenyl methacrylates
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作者 Bin Li Pan Zhou +2 位作者 Yuefei Chen Biao Jiang Hongping Zhu 《Science China Chemistry》 SCIE EI CAS CSCD 2015年第1期107-113,共7页
Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C(CH3)C(O)OC6H4F-4 (M^1a), H2... Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C(CH3)C(O)OC6H4F-4 (M^1a), H2C=C(CH3)C(O)OC6H4F-3 (M^1b), HEC=C(CH3)C(O)OC6H3F2-2,4 (M^2), H2C=C(CH3)C(O)OC6H2F3-2,3,4 (M^3), H2C=C(CH3)C(O)OC6HF4-2,3,5,6 (M^4), and H2C=C(CH3)C(O)OC6F5 (M^5) were synthesized and characterized. Initially, the polymerization was carded out on the monomer M^1a by using nBuLi, tBuLi, and KH as the respective catalysts; this approach produced the polymers in yields of 12%-50%, but with lower molecular weights. Similar results were obtained by using tBuLi for catalytically polymerizing the other five monomers. By introducing a co-catalyst MeAl(BHT)2, the catalysts Nail, LiH, and tBuOLi each were tested to polymerize M^1a, which gave the polymers in very low yields (3%-7%). Polymer yields of 13%-27% were obtained by each of the catalysts LiAlH4, nBuLi, PhLi, and tBuLi in connection with MeAI(BHT)2, but a better yield (61%) was achieved with KH/MeAl(BHT)2. The KH/MeAl(BHT)2 catalyst system was further employed to polymerize M^1b and M^2, which afforded respective polymer yields of 12%-63% and 10%-53%, depending on the molar ratios of KH:MeAl(BHT)2 as well as on the monomer concentrations. All of the polymers produced were syndiotactically rich in structure, as indicated by either ^1H or ^19F NMR data. The polymerization mechanism by the combined catalyst system is proposed. 展开更多
关键词 fluorophenyl methacrylates the combined catalyst system anionic polymerization syndiotactic polymer ^1H and ^19F NMR data
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