Controlled Radical Polymerization of Styrene by Reverse Iodine Transfer Polymerization (RITP) in Miniemulsion: Use of Hydrogen Peroxide as Oxidant (original) (raw)
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Comptes Rendus Chimie, 2003
The radical polymerization of styrene was investigated in the presence of diphenyl ditelluride (DPDTe) under varied conditions. In the polymerization without any radical initiator at higher temperature (125°C), the addition of DPDTe surely decreased the polymer molecular weight (M n ) while the polydispersity (M w /M n ) was rather broad. The polymerization with benzoyl peroxide (BPO) as the initiator was also uncontrollable to afford polymers with broad M w /M n probably due to the redox side reaction of BPO with DPDTe. On the contrary, the precision control of M n and the initiating end structure could be achieved by the polymerization with 2,2'azobisisobutyronitrile (AIBN), that is, M n increased in proportion to the molar ratio of monomer to initiator suggesting the suppression of bimolecular chain termination reactions by the excellent radical capturing ability of DPDTe.
Polymer, 2008
The control/livingness in nitroxide-mediated polymerization of styrene (S) in aqueous miniemulsion at 125 C employing a poly(S)-2,2,6,6-tetramethylpiperidinyl-1-oxy (PS-TEMPO) macroinitiator and the surfactant sodium dodecylbenzenesulfonate has been shown to depend strongly on the macroinitiator concentration for particles of approximate number-average diameter 65 nm. The control/livingness was relatively poor at [PS-TEMPO] 0 0.02 M due to the combined effect of enhanced spontaneous initiation and the interface effect (whereby deactivation is suppressed due to interfacial activity of TEMPO). Satisfactory control/livingness was obtained at higher [PS-TEMPO] 0 as a result of the interface effect and enhanced spontaneous initiation exerting less pronounced influence per chain than at lower [PS-TEMPO] 0. Polymerizations using the sulfonate surfactant DOWFAX 8390 gave similar results, indicating that the present macroinitiator concentration effects are not specific to SDBS-based systems. The results also demonstrate that TEMPO-mediated polymerization of S in miniemulsion can proceed at a higher rate than in bulk with good control/livingness.
Polymer, 2004
p-(Iodomethyl)styrene was polymerized under the action of a radical initiator (AIBN). The polymerization proceeds with degenerative chain transfer and leads to well defined branched polymers with functional primary and secondary iodomethyl groups as revealed by NMR studies. The obtained polymer can be further used as macroinitiator for radical polymerization of styrene. This polymerization proceeds in controlled way to polystyrene star polymers with reactive groups at the end of their arms. The characterization of branched and star structures was performed by NMR and GPC with absolute molar mass detection (MALLS). q
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European Polymer Journal, 1992
The kinetics of the polymerization of styrene in bulk and in dilute systems in the presence of p-acetyi benzylidene triphenylarsonium ylide (p-ABTAY) as radical initiator has been examined at 60+0.1°C for 20 h under N2. The values of the initiator exponent and the monomer exponent showed that the system follows ideal radical kinetics with bimolecular termination. The overall activation energy and average value of k~/k t are 64.6 kJ moi -1 and 0.10 × 10-21 mol -1 s -1, respectively. The ylide dissociates to produce phenyl radical, which brings about polymerization.
Colloid and Polymer Science, 2013
This study presents styrene emulsion polymerization initiated in aqueous media through an atom transfer radical polymerization (ATRP) mechanism. The water-soluble initiator employed in this process has been synthesized by our team by reacting diethanolamine with α-bromoisobutyryl bromide. The complexation of CuBr was realized by using a bicomponent complexation system comprised of 2,2′-bipyridine and N, N,N′,N′,N″-pentamethyldiethylenetriamine. The initiator ratio influence on the obtained emulsion was studied. The obtained latexes and polymer particles have been characterized by dynamic light scattering, scanning electron microscopy, and gel permeation chromatography.
Journal of Ultrafine Grained and Nanostructured Materials, 2019
A novel nano-initiator containing kojic acid moiety, [5-(benzyloxy)-4-oxo-4H-pyran-2-yl)methyl-2-bromo-2-methylpropanoate was synthesized by the reaction of 5-(benzyloxy)-2-(hydroxymethyl)-4H-pyran-4one with 2-bromoisobutyryl bromide in triethylamine and used as initiator in the atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate in the presence of Cu(0)/CuCl 2 and N,N,Nʹ,N″,N″pentamethyl diethylenetriamnie (PMDETA). The characteristics of resulting polymers were verified by proton nuclear magnetic resonance spectroscopy (1 H NMR), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). 1 H NMR spectra were recorded in deuterated chloroform (CDCl 3) with a Fourier transform (FT)-nuclear magnetic (NMR) spectrometer. To investigate the living nature of polymerization, the obtained polymers were subjected to further chain extension reaction. The chain extension of polystyrene (PS) and poly(methyl methacrylate) (PMMA) macroinitiators demonstrated that the chain ends of the obtained PS-Br and PMMA-Br were enable for further functionalization. After chain extension, the GPC curves shifted to high molecular weight. The values of number average molecular weight (M n) of PS and PMMA increased from 37853 to 40808 g/mol and from 107640 to 156310 g/mol, respectively. These results demonstrated that the chain extension reaction was successful and exhibited the living features of the chain end. To the best of our knowledge, the synthesis of ATRP initiator containing kojic acid moiety has not been reported. Herein, we report the synthesis and characterization of an ATRP initiator containing kojic acid moiety, and its application for the polymerzation of styrene and methyl methacrylate.