Libraries of Statistical Hydroxypropyl Acrylate Containing Copolymers with LCST Properties Prepared by NMP

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 110 °C 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 (T g), and the transition temperatures decreased from the T g of P(Amor) (147 °C) and P(DMA) (111 °C) to the T g of P(HPA) (22 °C) 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 88.0 °C and to 82.9 °C 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.

Synthesis and characterization of a novel temperature-pH responsive copolymer of 2-hydroxypropyl acrylate and aminoethyl methacrylate hydrochloric salt

“…The reason for this observation can be probably ascribed to the wider molecular weight distribution of copolymer or the different sequence of the monomer unit on copolymer chain. The wider phase transition temperature was also reported in another copolymer system from 2-hydroxylpropyl acrylate [19].…”

Construction of a Artificial Glutathione Peroxidase with Temperature‐Dependent Activity Based on a Supramolecular Graft Copolymer

“…[12] The optical transmission (600 nm) of PNIPAM-CD (1 mg· mL À1 ) was measured at different temperatures in a T60 UV/Vis spectrophotometer. Sample cells were thermostated in a circulator bath (28 to 40 8C) prior to measurement.…”

Synthesis and Postpolymerization Modification of Thermoresponsive Coatings Based on Pentaerythritol Monomethacrylate: Surface Analysis, Wettability, and Protein Adsorption

“…Among diversities of thermo-responsive polymers special attention should be paid to the polymers with hydroxyl groups [9][10][11][15][16][17][18][19][20], as they offer two advantages. Firstly, the polymers with hydroxyl fragments are low toxic as a rule [12][13][14].…”