Synthesis of multiarm star poly(glycerol)-block-poly(2-hydroxyethyl methacrylate)

Biomacromolecules
Yu ChenHolger Frey

Abstract

Well-defined multiarm star block copolymers poly(glycerol)-b-poly(2-hydroxyethyl methacrylate) (PG-b-PHEMA) with an average of 56, 66, and 90 PHEMA arms, respectively, have been prepared by atom transfer radical polymerization (ATRP) of HEMA in methanol by a core-first strategy. The hyperbranched macroinitiators employed were prepared on the basis of well-defined hyperbranched polyglycerol by esterification with 2-bromoisobutyryl bromide. Polydispersites M(w)/M(n) of the new multiarm stars were in the range of 1.11-1.82. Unexpectedly, with the combination of CuCl/CuBr(2)/2,2'-bipyridyl as catalyst, the polymerization conversion can be driven to maximum values of 79%. The control of CuCl catalyst concentration is also very important to achieve high conversion and narrow polydispersity. The absolute M(n) values of the obtained multiarm star polymers were in good agreement with the calculated ones, and the highest M(n) values of the multiarm star copolymer is around 10(6) g/mol. Kinetic analysis shows that an induction period exists in the polymerization of HEMA. After this induction period, a linear dependence of ln ([M](0)/[M](t)()) on time was observed. Due to the star architecture, the viscosity of the obtained multiarm star P...Continue Reading

References

Dec 13, 2001·Chemical Reviews·M KamigaitoM Sawamoto
Dec 26, 2001·Chemical Reviews·K Matyjaszewski, J Xia
Feb 22, 1991·Science·O W Webster

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Citations

Aug 13, 2010·Beilstein Journal of Organic Chemistry·Florian K WolfHolger Frey
May 22, 2008·Expert Opinion on Drug Delivery·María J VicentAntonio Pineda-Lucena
May 2, 2012·European Journal of Pharmaceutical Sciences : Official Journal of the European Federation for Pharmaceutical Sciences·Taryn R BagbyM Laird Forrest
Oct 20, 2011·Macromolecular Rapid Communications·Anja ThomasHolger Frey
Jul 1, 2016·Langmuir : the ACS Journal of Surfaces and Colloids·James Iocozzia, Zhiqun Lin

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