Enzymatic ring-opening block copolymers

Heise, Palmans, de Geus, Villarroya and their collaborators (17,41,42) have been working on a chemoenzymatic cascade synthesis to prepare block copolymers. They combine enzymatic ring-opening polymerization (eROP) and atom transfer radical polymerization (ATRP). The synthesis of block copolymers was successful in two consecutive steps, i.e., eROP followed by ATRP. In the one-pot approach, block copolymers could be obtained by sequential addition of the ATRP catalyst, but side reactions were observed when all components were present from at the onset of reactions. A successful one-pot synthesis was achieved by conducting the reaction in supercritical carbon dioxide. 

Fig. 12 Left. One-Pot enzymatic ring opening and iiving free radical cascade polymerization [44], Right. Block copolymers by combination of enzymatic ROP and carbene-catalyzed ROP [120]...

Thermoplastic poly(lactic acid) (PLA) is obtained by polycondensation of the acid or by ring-opening of the lactide. Its mechanical performance is similar to that of PS. Lactic acid (LA) can be produced by fermentation of coal, petroleum or namral gas. PLA is sensitive to enzymatic and chemical hydrolysis. It has been used for medical implants, dmg delivery, packaging and consumer goods. LA can be copolymerized with ethylene glycol into highly hydrophilic poly(ether-ester) block copolymers. Similarly, LA was copolymerized... 

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