Polyacrylates and Polydienes to High Conversion by a Stable Free Radical Polymerization Process:  Use of Reducing Agents

Keoshkerian, Barkev; Georges, Michaël K.; Quinlan, Marion H.; Veregin, Rick; Goodbrand, Bruce

doi:10.1021/ma971686r

Cited by 93 publications

(71 citation statements)

References 7 publications

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“…These results are quite unusual if compared to those obtained for polystyrene synthesized via SFRP under nearly identical conditions. High molecular weight polystyrene (M -n A 10 000 Dalton) can be obtained at similar rates in high yield by SFRP only if particular additives, which help to increase the rate of polymerization, are present in the reaction mixture [20][21][22][23] . It was observed that this approach was unnecessary for formation of PBBOS.…”

Section: Synthesismentioning

confidence: 99%

Mesogen-jacketed liquid crystalline polymers via stable free radical polymerization

Pragliola

Ober

Mather

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: Stable free radical polymerization has been used in the controlled synthesis of poly (2,5-bis[(4-butylbenzoyl)oxy]styrene), PBBOS. This "mesogen-jacketed liquid crystalline polymer", which has mesogenic units attached directly to the backbone in a side-on mode, has been found to exhibit thermotropic liquid crystallinity similar to more conventional main-chain architectures. Stable free radical polymerization of PBBOS consistently produced molecular weight distributions below the theoretical limiting polydispersity of 1.5 calculated for a conventional free radical polymerization process. Surprisingly, a comparison of the synthesis of polystyrene to the polymerization of PBBOS under nearly identical conditions showed that the PBBOS polymerized with a significantly higher reaction rate and monomer conversion efficiency. The nematic phase of these polymers was determined to be stable over the temperature range spanning the polymer glass transition temperature up to the temperature for thermal decomposition. The molecular arrangement of the PBBOS polymers was examined by wide-angle X-ray diffraction and is described here.

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Section: Synthesismentioning

confidence: 99%

Mesogen-jacketed liquid crystalline polymers via stable free radical polymerization

Pragliola

Ober

Mather

et al. 1999

Macromol. Chem. Phys.

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“…For instance, functional TEMPO, such as 4-oxo-TEMPO, was used in the polymerization of styrene and acrylates [10]. Later on, more active acyclic nitroxides containing an α-hydrogen, such as DEPN (N-tert-butyl-N-(1-di-ethylphosphono-2,2-dimethylpropyl)-N-oxyl) [11][12][13][14][15][16][17] and TIPNO (2,2,5,5-tetramethyl-4-phenyl-3-azahexane-3-oxyl) [18] and [19], were developed with great success in the controlled radical polymerization of a broader range of monomers, including styrene and derivatives, acrylates, acrylamide, acrylonitrile, acrylic acid and dienes.…”

Section: Introductionmentioning

confidence: 99%

Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides

Sciannamea

Guerrero‐Sánchez

Schubert

et al. 2005

Polymer

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The ability of several nitrones to control the radical polymerization of styrene at 110 °C has been investigated by high-throughput experimentation. The nitrone/free radical initiator pair dictates the structure of the nitroxide and the alkoxyamine formed in situ, which determines the position of the equilibrium between the active and the dormant species operating in the nitroxide-mediated polymerization. For the styrene polymerization to be controlled, the nitrone must be reacted with 2,2′-azo-bis-isobutyronitrile (AIBN) at 85 °C, prior to addition of styrene and polymerization at 110 °C. The effect of the nitrone structure on the kinetics of the styrene polymerization has been emphasized. Amongst all the nitrones tested, those of the C-phenyl-N-tert-butylnitrone (PBN) type are the most efficient in terms of polymerization rate, control of molecular weight and polydispersity. Electrophilic substitution of the phenyl group of PBN by either an electrodonor or an electroacceptor group has only a minor effect on the polymerization kinetics. Importantly, the polymerization rate is not governed by the thermal polymerization of styrene but by the alkoxyamine formed in situ during the pre-reaction step. The initiation efficiency is, however, very low, consistent with a limited conversion of the nitrone into nitroxide and alkoxyamine.

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“…By means of UV-VIS spectroscopy the reduction of the concentration of free TEMPO through reaction with acetic anhydride at 125 8C in ethylbenzene was demonstrated. method represents the reduction of the nitroxyl concentration, for example by means of glucoses, [12] acids [10, 13 -15] or acid anhydrides. [16,17] The application of acid anhydrides for the acceleration of SFRP of styrene was first introduced by Malmström et al [16] They analyzed the effect of various additives on the SFRP and found that the addition of small amounts of acetic anhydride (Ac 2 O) results in a decreased reaction time without any loss of control.…”

Section: Introductionmentioning

confidence: 99%

Acetic Anhydride - Accelerating Agent for Nitroxide-Controlled Free-Radical Copolymerization of Styrene and Acrylonitrile

Baumann

Schmidt‐Naake²

2001

Macromol. Chem. Phys.

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The stereoselective hydrogenation of oxazolidinone‐substituted pyridines shown in the cover picture gives piperidines containing up to four new stereocenters. One of the biologically active compounds readily accessible by this method is (S)‐coniine, the poisonous hemlock alkaloid used in ancient Greece for executions. The famous painting by David shows Socrates shortly before drinking from the poison chalice. F. Glorius et al. describe this synthetic method on pages 2850 ff.

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Polyacrylates and Polydienes to High Conversion by a Stable Free Radical Polymerization Process: Use of Reducing Agents

Cited by 93 publications

References 7 publications

Mesogen-jacketed liquid crystalline polymers via stable free radical polymerization

Mesogen-jacketed liquid crystalline polymers via stable free radical polymerization

Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides

Acetic Anhydride - Accelerating Agent for Nitroxide-Controlled Free-Radical Copolymerization of Styrene and Acrylonitrile

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