Synthesis and Thermal Properties of Well-Defined Amphiphilic Block Copolymers Based on Polyglycidol
Synthesis and Thermal Properties of Well-Defined Amphiphilic Block Copolymers Based on Polyglycidol
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DOI：
10.1021/ma902854r
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发表时间：
2010-04-13
期刊：
影响因子：
5.5
通讯作者：
Moeller, Martin
中科院分区：
文献类型：
--
作者：
Backes, Marco;Messager, Lea;Moeller, Martin
合成了一系列用三种不同烷基侧链（烷基链长= C-12、C-14和C-16）官能化的两亲性嵌段共聚物，并通过NMR光谱、凝胶渗透色谱（GPC）和差示扫描量热法（DSC）进行分析。在四步合成中获得嵌段共聚物。在第一步中，乙氧基乙基缩水甘油醚（EEGE）和叔丁基缩水甘油醚（tBuGE）通过阴离子机理依次聚合。在下一步骤中，选择性地除去EEGE重复单元的缩醛保护基团，并使所获得的羟基与异氰酸烷基酯反应。最后，除去叔丁基醚保护基团。合成的所有步骤均通过H-1 NMR光谱、GPC和DSC分析进行控制。所有嵌段聚合物显示三个热转变，无论旧链长度的异氰酸酯使用：玻璃化转变特性的聚缩水甘油骨干和两个吸热峰，与熔融的脂肪族侧链和随后的断裂的氢键由于氨基甲酸酯基团。这种热行为表明，二嵌段共聚物自组装成微区，其稳定性（存在）可以随温度调节。
A series of amphiphilic block copolymers functionalized with three different alkyl side chains (alkyl chain length = C-12, C-14, and C-16) were synthesized and analyzed via NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). The block copolymers were obtained in a four-step synthesis. In the first step ethoxy ethyl glycidyl ether (EEGE) and tert-butyl glycidyl ether (tBuGE) were sequentially polymerized via an anionic mechanism. In the next step, the acetal protection groups of EEGE repeating units were selectively removed and the hydroxyl groups obtained were reacted with alkyl isocyanates. Finally, the tert-butyl ether protection groups were removed. All steps of the synthesis were controlled via H-1 NMR spectroscopy, GPC, and DSC analyses. All block polymers showed three thermal transitions regardless oldie chain length of the isocyanate used: a glass transition characteristic for the polyglycidol back bone and two endothermic peaks, associated with melting of the aliphatic side chains and subsequent breakdown of the hydrogen bonds due to the urethane groups. This thermal behavior suggests that diblock copolymers self-assemble into microdomains whose stability (existence) can be tuned with temperature.