A switch from anionic to bifunctional H-bonding catalyzed ring-opening polymerizations towards polyether–polyester diblock copolymers
A switch from anionic to bifunctional H-bonding catalyzed ring-opening polymerizations towards polyether–polyester diblock copolymers
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DOI：
10.1039/c7py01842h
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发表时间：
2018
影响因子：
4.6
通讯作者：
Yaya Liu;Xin Wang;Zhenjiang Li;Fulan Wei;Huixuan Zhu;He Dong;Si-Jie Chen;He-Yi Sun;Kun Yang;Kai Guo
中科院分区：
文献类型：
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作者：
Yaya Liu;Xin Wang;Zhenjiang Li;Fulan Wei;Huixuan Zhu;He Dong;Si-Jie Chen;He-Yi Sun;Kun Yang;Kai Guo
结构不同的环氧化物和环酯的共聚提供了聚醚-嵌段-聚酯共聚物，其是有价值的合成材料。然而，缩水甘油醚的阴离子开环聚合（ROP）通常与随后的丙交酯（LA）的ROP不相容。我们设计了一种由四丁基氟化铵引发缩水甘油苯基醚（GPE）的ROP，然后加入硫脲（TU）引发LA的ROP的可切换方法。第一ROP的活性醇盐链端转变为醇，TU转变为硫脲阴离子（TUA）。TUA通过双官能氢键催化促进了LA从醇的ROP，以受控/活性的方式完全转化为单体。在室温下，在溶液中制备了具有精确分子量和窄分散度（ε，1.13至1.19）的聚（GPE-b-LA）。1H NMR滴定表明TUA的形成及其与链端羟基的配位，这在ROP的开关和H-键合催化LA的ROP中起关键作用。阴离子到氢键的可切换催化剂显示了将环氧化物和环酯共聚成二嵌段共聚物的通用且简单的协议。
The copolymerization of structurally distinct epoxides and cyclic esters offers polyether-block-polyester copolymers which are valuable synthetic materials. However, the anionic ring-opening polymerization (ROP) of glycidyl ethers is not usually compatible with the subsequent ROP of lactide (LA). We designed a switchable approach composed of the tetrabutylammonium fluoride initiated ROP of glycidyl phenyl ether (GPE), followed by the addition of thiourea (TU) to initiate the ROP of LA. The active alkoxide chain end of the first ROP was turned into an alcohol, and the TU was turned into a thioureate anion (TUA). The TUA promoted the ROP of LA from the alcohol via bifunctional H-bonding catalysis to full monomer conversion in a controlled/living manner. Poly(GPE-b-LA) with precise molecular weights and narrow dispersities (Đ, 1.13 to 1.19) were prepared at room temperature in solution. 1H NMR titrations suggested the formation of the TUA and its coordination with chain end hydroxyl; this played key roles in the switch of ROPs and H-bonding catalyzed ROP of LA. The anionic to H-bonding switchable catalysis showed a general and simple protocol to copolymerize epoxides and cyclic esters into diblock copolymers.