ATRP法合成二十元、二十八元线形环化聚合物

Synthesis of Linear Cyclopolymers with 20 and 28-Membered Rings by ATRP

采用以甲苯为聚合介质的ATRP聚合体系,以双甲基丙烯酸二醇酯为单体,合成了具有二十和二十八元环的线形环化聚合物,聚合物具有窄分子量分布.聚合动力学显示随着链长的增加,环化反应速率变慢.根据聚合物的1H-NMR谱图、由1H-NMR端基分析得到聚合度DPNMR、以及GPC图谱结果,证实获得了线形环化聚合物.TGA测试结果表明2种聚合物的起始分解温度均大于372℃,具有比PMMA更好的热稳定性.

Linear cyclopolymers with 20- and 28- membered rings were synthesized respectively by ATRP.Cyclopolymerization was carried out using Cu Br / PMDETA / EBi B as an initiating system with toluene as solvent,which favored intramolecular cyclization over that with DMSO as solvent. The polymerization kinetics showed that the rate of cyclopolymerization reduced with increasing the ring-size of the polymers. Cyclization efficiency of dialkylsilylene-tethered bismethacrylates is highly affected by the monomer concentration,with the increasing of the concentration of monomer,the cyclization efficiency decreases and PDI of polymer obtained becomes broad. The cyclic structures of the polymer were confirmed by the1H-NMR spectroscopy and the cyclic degree of the polymers was determined by the end-group analysis of the cyclopolymers and GPC.1HNMR spectroscopy indicated that the polymerizations proceeded with 95% cyclization for monomer A2 and92% cyclization for monomer B2. The polymers show controlled molecular weights and narrow molecular weight distributions（ Mw/ Mn〈 1. 3）. The thermodynamic properties of the cyclopolymers was investigated by TGA.The results showed that the cyclopolymers have higher thermal stability（ 〉 372 ℃） than poly（ methyl methacrylate）.