二苯基碘鎓盐引发氨酯型乙烯基醚热聚合

合成了2种固态氨酯型乙烯基醚PUE1和PUE2,并对其结构和性能进行了表征.研究发现,二芳基碘六氟磷酸盐(PI810)能引发PUE1和PUE2发生阳离子热聚合,热聚合温度远低于PI810的纯态热分解温度,且聚合转化率很高.初步认为热聚合机理是富电子的乙烯基醚双键和缺电子的二苯基碘盐阳离子之间形成中间态电荷转移复合物,降低了二苯基碘盐的热分解温度,进而生成引发活性种乙烯基醚阳离子自由基或质子酸,引发乙烯基醚的阳离子聚合反应.

Thermal Polymerization of Urethane Vinyl Ethers Initiated by Diaryldiodonium Salt

Two solid vinyl ether terminated aliphatic urethanes, named PUE1 and PUE2, were synthesized and characterized. PUE1 is a crystalline compound with a melting point of 101 ℃; PUE2 is a prepolymer with glass transition temperatures of 30.8 and 17.2 ℃. Both compounds undergo rapid thermal polymerization in the presence of diphenyliodonium hexafluorophosphate(PI810) at different temperatures. The thermal polymerization temperatures for these systems are much lower than the thermal decomposition temperature of neat PI810. The initiation mechanism is presumably based on the electron transfer from electron-rich vinyl ether to electron-dificient diphenyliodonium salt, forming an intermediate charge transfer complex, which can undergo rapid electron transfer or decompose to give radical-cationic vinyl ether or protonic acid, both of which are responsible for the initiation of vinyl ether cationic polymerization.