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Conventional Radical Polymerizations (conventional + radical_polymerization)
Selected AbstractsAtom Transfer Radical Polymerization of Glycidyl Methacrylate: A Functional MonomerMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2004Pedro Francisco Cañamero Abstract Summary: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed. Homopolymers were prepared at relatively low temperatures using ethyl 2-bromoisobutyrate (EBrIB) as the initiator and copper halide (CuX) with N,N,N,,N,,N,-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The high polymerization rate in the bulk did not permit polymerization control. However, homopolymerization in solution enabled us to explore the effects of different experimental parameters, such as temperature, solvent (toluene vs. diphenyl ether) and initiator concentration, on the controllability of the ATRP process. SEC analysis of the homopolymers synthesized confirmed the importance of solvent character on molecular weight control, the lowest polydispersity indices () and the highest efficiencies being found when the polymerizations were performed in diphenyl ether in combination with a mixed halide technique. A novel poly(glycidyl methacrylate)- block -poly(butyl acrylate) (PGMA- b -PBA) diblock copolymer was prepared through ATRP using PGMA-Cl as a macro-initiator. This chain growth experiment demonstrated a good living character under the conditions employed, while simultaneously indicating a facile synthetic route for this type of functional block copolymer. In addition, the isotacticity parameter for the PGMAs obtained was estimated using 1H NMR analysis which gave a value of ,GMA,=,0.26 in agreement with that estimated in conventional radical polymerization. SEC chromatograms of PGMA-Cl macroinitiator and PGMA- b -PBA diblock copolymer. [source] Stability and utility of pyridyl disulfide functionality in RAFT and conventional radical polymerizationsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2008Cyrille Boyer Abstract Two RAFT agents, suitable for inducing living radical polymerization in water, have been synthesized. Both RAFT agents were shown to be effective over the temperature range 25,70 °C. One RAFT agent was functionalized with a pyridyl disulfide group. RAFT efficacy was demonstrated for the polymerizations of N -isopropyl acrylamide (NIPAAM) and poly(ethylene oxide)-acrylate (PEG-A) in both water and acetonitrile. The kinetic data indicates that the pyridyl disulfide functionality is largely benign in free radical polymerizations, remaining intact for subsequent reaction with thiol groups. This result was confirmed by studying conventional radical polymerizations in the presence of hydroxyethyl pyridyl disulfide. The utility of the pyridyl disulfide functionality at the terminus of the polymers was demonstrated by synthesizing polymer-BSA conjugates. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7207,7224, 2008 [source] Nitroxide-Mediated Radical Polymerization of N - tert -ButylacrylamideMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 23 2008Orla Gibbons Abstract The nitroxide-mediated polymerization of N - tert -butylacrylamide (TBAM) in DMF at 120,°C using SG1/DEPN and AIBN has been investigated. Linear growth in number-average molecular weight () versus conversion and narrow molecular weight distributions (MWDs) with high livingness were obtained up to ,8,000 g,·,mol,1. For higher molecular weights, the MWDs gradually became broader with low molecular weight tailing, and deviated downwards from theoretical values. Quantitative analyses of MWDs, along with specifically designed conventional radical polymerizations at 120,°C, were consistent with chain transfer to monomer limiting the attainable . This finding can be equally applied to existing literature polymerizations of TBAM. [source] | ||||||||||