Synthesis and characterization of diblock and triblock copolymer by enzymatic ring-opening polymerization of ε-caprolactone and ATRP of styrene

摘要

Diblock and triblock copolymer of ε-caprolactone(ε-CL) and styrene(St) were obtained by the combination of two different polymerization process, namely enzymatic ring-opening polymerization(ROP) and atom transfer radical polymerization(ATRP) methods. Mono-/di- hydroxyl terminated macromolecules were prepared by enzymatic ROP of ε-CL in the presence of Novozyme-435 and methanol/ethylene glycol as biocatalyst and initiator, respectively, and subsequently converted to bromine ended polycaprolactone(PCL) by the esterification of the resulting macromolecules with α-bromopropionyl bromide. The mono- and difunctional macroinitiators were employed in ATRP of styrene using CuCl/2, 2’-bipyridine(bpy) as the catalyst system. The GPC and 1H-NMR analysis indicated a controlled/living radical polymerization which resulted in the formation of block copolymers with narrow polydispersities.