Libraries of statistical hydroxypropyl acrylate containing copolymers with LCST properties prepared by NMP

T.M. Eggenhuisen, C.R. Becer, M.W.M. Fijten, R. Eckardt, R. Hoogenboom, U.S. Schubert

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93 Citations (Scopus)

Abstract

The nitroxide-mediated copolymerization of 2-hydroxypropyl acrylate (HPA) with N-acryloylmorpholine (Amor) or N,N-dimethylacrylamide (DMA) was investigated using N-tert-butyl-N-(1?-diethylphosphono-2,2?- dimethylpropyl)-O-(2-carboxyl-prop-2-yl) (BlocBuilder) alkoxyamine initiator and additional free nitroxide (SG-1). Different reaction conditions, such as the concentration of additional SG-1, were tested to optimize the homopolymerizations using a Chemspeed ASW2000 automated parallel synthesizer. Best control for the homopolymerizations (polydispersity indices of 1.2-1.3) of all three monomers was achieved using 20% additional SG-1 (relative to the initiator) at a reaction temperature of 110ÝC for 2 M solutions in N,N-dimethylformamide and a monomer/initiator ratio of 100/1. Libraries of P(Amor-stat-HPA) and P(DMA-stat-HPA) were synthesized with 0-100 mol % HPA with 10 mol % increments using the optimized conditions obtained for the homopolymerizations. The resulting polymers had narrow molecular weight distributions, and their compositions, determined using 1H NMR spectroscopy and elemental analysis, were close to the theoretical compositions. In addition, all copolymers of both libraries had single glass transition temperatures (Tg), and the transition temperatures decreased from the Tg of P(Amor) (147ÝC) and P(DMA) (111ÝC) to the T g of P(HPA) (22ÝC) with increasing HPA content. The cloud point of P(HPA) showed concentration dependence as well as a concentration dependent hysteresis. The cloud points of aqueous solutions of the copolymer libraries could be tuned from 21.4 to 88.0ÝC and to 82.9ÝC for P(Amor-stat-HPA) and P(DMA-stat-HPA), respectively, at a concentration of 1 wt %. LCST behavior was observed for copolymers with >40 wt % HPA in P(Amor-stat-HPA) and >55 wt % HPA in the P(DMA-stat-HPA) library. © 2008 American Chemical Society
Original languageEnglish
Pages (from-to)5132-5140
JournalMacromolecules
Volume41
Issue number14
DOIs
Publication statusPublished - 2008

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