tBHBMA: a novel trifunctional acrylic monomer for the convenient synthesis of PAA-g-PCL well-defined amphiphilic graft copolymer
tBHBMA: a novel trifunctional acrylic monomer for the convenient synthesis of PAA-g-PCL well-defined amphiphilic graft copolymer
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DOI：
10.1039/c3py00046j
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发表时间：
2013-04
影响因子：
4.6
通讯作者：
Xue‐Zhi Song;Wenqiang Yao;Guolin Lu;Yongjun Li;Xiaoyu Huang
中科院分区：
文献类型：
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作者：
Xue‐Zhi Song;Wenqiang Yao;Guolin Lu;Yongjun Li;Xiaoyu Huang
采用可逆加成-断裂链转移（RAFT）和开环聚合（ROP）相结合的方法合成了一系列由亲水性聚丙烯酸（PAA）主链和疏水性聚己内酯（PCL）侧链组成的两亲性接枝共聚物。以丙烯酸叔丁酯为起始原料，合成了一种含ROP引发基团的丙烯酸叔丁酯（2-（（4-羟基丁酰氧基）甲基）丙烯酸酯），并通过RAFT进行了可控均聚，得到了结构清晰的均聚物。该均聚物直接引发ε-己内酯的ROP，通过接枝策略提供定义明确的聚（丙烯酸叔丁酯）-g-聚（ε-己内酯）接枝共聚物，而无需聚合后官能度转化。最后，疏水的聚（丙烯酸叔丁酯）主链在酸性环境中选择性水解而不影响PCL侧链，得到具有亲水性PAA主链和均匀分布的疏水性PCL侧链的聚（丙烯酸）-g-聚（ε-己内酯）两亲性接枝共聚物。通过荧光光谱、动态光散射和透射电镜研究了两亲性接枝共聚物的自组装行为和胶束的pH敏感性。DSC和XRD分析表明了聚丙烯酸-g-聚己内酯接枝共聚物的结晶行为。
A series of well-defined amphiphilic graft copolymers, consisting of a hydrophilic poly(acrylic acid) (PAA) backbone and hydrophobic poly(e-caprolactone) (PCL) side chains, was synthesized by the combination of reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP). A new acrylate monomer containing a ROP initiation group, tert-butyl(2-((4-hydroxybutanoyloxy)methyl)acrylate), was first prepared using tert-butyl acrylate as the starting material, and it was homopolymerized by RAFT in a controlled way to give a well-defined homopolymer bearing ROP initiation group in every repeating unit. This homopolymer directly initiated ROP of e-caprolactone to provide well-defined poly(tert-butyl acrylate)-g-poly(e-caprolactone) graft copolymers via the grafting-from strategy without post-polymerization functionality transformation. Finally, the hydrophobic poly(tert-butyl acrylate) backbone was selectively hydrolyzed in an acidic environment without affecting the PCL side chains to afford poly(acrylic acid)-g-poly(e-caprolactone) amphiphilic graft copolymers possessing the hydrophilic PAA backbone and equally distributed hydrophobic PCL side chains. The self-assembly behavior of the obtained amphiphilic graft copolymers and pH-sensitivity of the resultant micelles were investigated by fluorescence spectroscopy, DLS, and TEM. DSC and XRD analysis showed the crystallization behavior of poly(acrylic acid)-g-poly(e-caprolactone) graft copolymers.