Stereosequenced crystalline polyhydroxyalkanoates from diastereomeric monomer mixtures
Stereosequenced crystalline polyhydroxyalkanoates from diastereomeric monomer mixtures
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DOI：
10.1126/science.aax8466
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发表时间：
2019-11-08
期刊：
影响因子：
56.9
通讯作者：
Chen, Eugene Y. -X.
中科院分区：
文献类型：
--
作者：
Tang, Xiaoyan;Westlie, Andrea H.;Chen, Eugene Y. -X.
Stereoselective polymerization of chiral or prochiral monomers is a powerful method to produce high-performance stereoregular crystalline polymeric materials.然而，对于具有两个立构中心的单体，通常需要在聚合前分离非对映异构体，导致大量的材料损失以及与分离和纯化过程相关的能量成本的增加。 Here we report a diastereoselective polymerization methodology enabled by catalysts that directly polymerize mixtures of eight-membered diolide (8DL) monomers with varying starting ratios of chiral racemic (rac) and achiral meso diastereomers into stereosequenced crystalline polyhydroxyalkanoates with isotactic and syndiotactic stereodiblock or stereotapered block microstructures. These polymers show enhanced ductility and toughness relative to polymers of pure rac-8DL, subject to tuning by variation of the diastereomeric ratio and structure of the 8DL monomers.
Stereoselective polymerization of chiral or prochiral monomers is a powerful method to produce high-performance stereoregular crystalline polymeric materials. However, for monomers with two stereogenic centers, it is generally necessary to separate diastereomers before polymerization, resulting in substantial material loss and added energy cost associated with the separation and purification process. Here we report a diastereoselective polymerization methodology enabled by catalysts that directly polymerize mixtures of eight-membered diolide (8DL) monomers with varying starting ratios of chiral racemic (rac) and achiral meso diastereomers into stereosequenced crystalline polyhydroxyalkanoates with isotactic and syndiotactic stereodiblock or stereotapered block microstructures. These polymers show enhanced ductility and toughness relative to polymers of pure rac-8DL, subject to tuning by variation of the diastereomeric ratio and structure of the 8DL monomers.