A switch from anionic to bifunctional H-bonding catalyzed ring-opening polymerizations towards polyether–polyester diblock copolymers†,Polymer Chemistry

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A switch from anionic to bifunctional H-bonding catalyzed ring-opening polymerizations towards polyether–polyester diblock copolymers†
Polymer Chemistry ( IF 4.1 ) Pub Date : 2017-12-05 00:00:00 , DOI: 10.1039/c7py01842h
Yaya Liu _{1,

2,

3,

4,

5} , Xin Wang _{1,

2,

3,

4,

5} , Zhenjiang Li _{1,

2,

3,

4,

5} , Fulan Wei _{1,

2,

3,

4,

5} , Hui Zhu _{1,

2,

3,

4,

5} , He Dong _{1,

2,

3,

4,

5} , Siming Chen _{1,

2,

3,

4,

5} , Herui Sun _{1,

2,

3,

4,

5} , Kun Yang _{1,

2,

3,

4,

5} , Kai Guo _{1,

2,

3,

4,

5}

Affiliation

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.

中文翻译：

从阴离子型到双功能的H键催化开环聚合向聚醚-聚酯二嵌段共聚物的转变†

结构不同的环氧化物和环状酯的共聚提供了聚醚嵌段聚酯共聚物，这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。我们设计了一种可切换的方法，该方法由四丁基氟化铵引发的缩水甘油基苯基醚（GPE）引发ROP，然后添加硫脲（TU）引发LA的ROP。第一个ROP的活性醇盐链末端变成了醇，TU变成了硫脲酸根阴离子（TUA）。TUA通过双功能氢键催化以受控/活性方式将LA的ROP从醇中提升为完全单体转化。聚（GPE- b在室温下，在溶液中制备具有精确分子量和窄分散度（-1.13至1.19）的-LA）。¹ H NMR滴定表明TUA的形成及其与链端羟基的配位；这在LA的ROP和H键催化的ROP转换中起着关键作用。阴离子到H键的可转换催化反应显示出将环氧化物和环酯共聚成二嵌段共聚物的一般且简单的方案。

更新日期：2017-12-05

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