Intrachain Cyclization via Postmodification of the Internal Alkenes of Periodic ADMET Copolymers: The Sequence Matters
作者:Zi-Long Li、An Lv、Fu-Sheng Du、Zi-Chen Li
DOI:10.1021/ma5013732
日期:2014.9.9
acrylate units was synthesized via a two-step approach. The acyclic diene metathesis (ADMET) polymerization of monomer 1 was conducted with a Hoveyda–Grubbs second generation catalyst in the presence of p-benzoquinone to get well-defined polymer (P1) with high molecular weights as revealed by GPC, NMR, and MALDI-TOF-MS characterizations. Dihydroxylation of P1 using hydrogen peroxide as the oxidant was successfully
我们表明,单体序列是很重要的,以调节乙烯基共聚物通过链内的环化的热特性。这是通过自发的链内环化和通过设计的周期共聚物的内部烯烃的二羟基化形成γ-丁内酯来举例说明的。结构上对称的α,ω -二烯单体1含有两个尾对尾连接的丙烯酸乙酯单元被通过两步骤的方法合成的。的单体的无环二烯复分解(ADMET)聚合1用在存在一个格拉布第二代催化剂进行p醌获得良好定义的聚合物(P1GPC,NMR和MALDI-TOF-MS表征表明具有高分子量)。的二羟基化P1使用过氧化氢作为氧化剂被成功地进行,得到HP1。表征HP1通过NMR和IR光谱表明,它含有γ丁内酯单元在聚合物主链上。用四种不同的聚合物的对照实验表明,该环结构的形成是通过二羟基化的形成乙烯醇-丙烯酸乙酯的特定序列的结果P1。的环化效率P1经计算为77%。的Ť克与不饱和样品相比,所有改性聚合物的比值均增加。明显地,与P1相比,HP1的T g急剧升高了160℃