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See detailThe in situ formation of a new initiator system for the syndiotactic anionic polymerization of methyl methacrylate in toluene at 0°C
Zundel, Thomas; Teyssié, Philippe; Jérôme, Robert ULg

in Polymer (2002), 43(25), 7191-7193

This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 °C ... [more ▼]

This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 °C. Predominantly syndiotactic PMMA is formed. [less ▲]

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See detailControl of the radical polymerization of tert-butyl methacrylate in water by a novel combination of sodium nitrite and iron(II) sulfate
Detrembleur, Christophe ULg; Teyssié, Philippe; Jérôme, Robert ULg

in Macromolecules (2002), 35(5), 1611-1621

Addition of iron(II) sulfate to sodium nitrite is a new way to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80 degreesC. Nitric oxide is released in the reaction medium ... [more ▼]

Addition of iron(II) sulfate to sodium nitrite is a new way to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80 degreesC. Nitric oxide is released in the reaction medium as result of the reduction of sodium nitrite by FeSO4. This reaction is of utmost importance because three repeated additions of an alkyl radical to nitric oxide leads to the formation of nitroxide radicals. The basic mechanism for the control of the radical polymerization is thus a nitroxide-mediated process. [less ▲]

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See detailLithiation of toluene by organolithium compounds activated by lithium polyether alkoxides
Nugay, Nihan; Nugay, Turgut; Jérôme, Robert ULg et al

in Journal of Molecular Catalysis A: Chemical (2002), 179(1-2), 59-64

The catalytic effect of polyether alkoxides (PEAs) on the activity of organolithium. compounds as metallating agent has been investigated. Toluene has been lithiated by using different organolithiums ... [more ▼]

The catalytic effect of polyether alkoxides (PEAs) on the activity of organolithium. compounds as metallating agent has been investigated. Toluene has been lithiated by using different organolithiums activated by various PEAs. It has been found that n-BuLi, yields higher conversion with 100% benzylic position metallation, whereas sec-BuLi gives some metallation at ring positions with the most reactive ligand, lithium 2-methoxy ethoxide (LiOEM). Optimum PEA to organolithium molar ratio for both sec- and n-BuLi activated by LiOEM where the amount of toluene being kept constant, was found to be as 3:1 with highest yield and regioselectivity. Substantial increment in yield was observed when the amount of substrate increased whereas regioselectivity stayed almost constant. It was also found that, for a constant reactant molar ratio (3:1:15) for which the optimum results were achieved, reaction began early and then yield values increased with time whereas upon increase in reaction temperature from -78 to 20degreesC, the benzylic metallation yield increased drastically while keeping the same regioselectivity high. [less ▲]

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See detailSodium nitrite and ascorbic acid: a metal-free combination that controls the free-radical polymerization of tert-butyl methacrylate in water
Detrembleur, Christophe ULg; Mouithys-Mickalad, Ange ULg; Teyssié, Philippe et al

in e-Polymers (2002), (4), 1-16

A mixture of sodium nitrite and ascorbic acid is able to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80°C. Indeed, sodium nitrite is reduced by the ascorbic acid, and ... [more ▼]

A mixture of sodium nitrite and ascorbic acid is able to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80°C. Indeed, sodium nitrite is reduced by the ascorbic acid, and the nitric oxide (NO) which is formed in situ is nothing but a promoter of nitroxyl radicals. The radical polymerization of tBMA is thus basically controlled by a nitroxide-mediated process. [less ▲]

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See detailSynthesis of fully acrylic thermoplastic elastomers by atom transfer radical polymerization (ATRP), 2a effect of the catalyst on the molecular control and the rheological properties of the triblock copolymers
Moineau, Georges; Minet, Michaël; Teyssié, Philippe et al

in Macromolecular Chemistry and Physics (2000), 201(11), 1108-1114

The ATRP of MMA was initiated by α,ω-dibromo poly(n-butyl acrylate) in the presence of NiBr2(PPh3)2 leading to poly(MMA)-b-poly(nBuA)-b-poly(MMA) triblock copolymers (MnBM). The initiation of the MMA ... [more ▼]

The ATRP of MMA was initiated by α,ω-dibromo poly(n-butyl acrylate) in the presence of NiBr2(PPh3)2 leading to poly(MMA)-b-poly(nBuA)-b-poly(MMA) triblock copolymers (MnBM). The initiation of the MMA polymerization is slow compared to the chain propagation, which results in PMMA blocks of broad molecular weight distribution (MWD). In order to improve this situation, several experimental parameters were varied. CuBr/dNBipy was first substituted for NiBr2(PPh3)2, the results being, however, even worse. Then, the halide exchange was considered by substituting CuCl for CuBr. The CuCl/dNBipy catalyst proved superiority over the originally used NiBr2(PPh3)2 system. Finally, the addition of an excess of CuCl2 (deactivator) to the CuCl/dNBipy catalyst was very beneficial in decreasing the MWD of the PMMA blocks. Indeed, the SEC chromatograms are monomodal and narrow from the very beginning of the polymerization. The rheological analysis of the MnBM triblocks synthesized in the presence of each of the aforementioned catalytic systems confirmed differences in the molecular control of the copolymeriza-tion reaction. [less ▲]

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See detailSynthesis and characterization of poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) copolymers by two-step controlled radical polymerization (ATRP) catalyzed by NiBr2(PPh3)2, 1+
Moineau, Georges; Minet, Michaël; Teyssié, Philippe et al

in Macromolecules (1999), 32(25), 8277-8282

Poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) triblock copolymers (MnBM) have been synthesized by the sequential controlled radical polymerization (atom transfer ... [more ▼]

Poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) triblock copolymers (MnBM) have been synthesized by the sequential controlled radical polymerization (atom transfer radical polymerization, ATRP) of n-butyl acrylate (n-BuA) followed by methyl methacrylate (MMA). The polymerization of n-BuA has been first initiated by the difunctional (diethyl meso-2,5-dibromoadipate) initiator in the presence of the NiBr2(PPh3)2 catalyst. After isolation, the α,ω-dibromo poly(n-butyl acrylate) chains have been used as macroinitiators for the polymerization of either n-BuA or MMA leading to chain extension or to the desired triblock copolymers, respectively. The kinetic study of the two-step process has shown that the initiation of the MMA polymerization by the poly(n-BuA) macroinitiator is slow and leads to PMMA outer blocks of broad polydispersity. Differential scanning calorimetry (DSC) and dynamical mechanical analysis (DMA) have confirmed the two-phase morphology of the triblocks. Finally, DMA and tensile testing of these copolymers have emphasized poor mechanical properties in possible relation to the broad polydispersity of the PMMA outer blocks. [less ▲]

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See detailControlled radical polymerization of (meth)acrylates by ATRP with NiBr2(PPh3)2 as catalyst
Moineau, Georges; Minet, Michaël; Dubois, Philippe ULg et al

in Macromolecules (1999), 32(1), 27-35

NiBr2(PPh3)2 has been found to be an efficient catalyst for the ATRP of methyl methacrylate (MMA) and n-butyl acrylate (n-BuA) initiated by an alkyl halide in the absence of any activator (e.g., Lewis ... [more ▼]

NiBr2(PPh3)2 has been found to be an efficient catalyst for the ATRP of methyl methacrylate (MMA) and n-butyl acrylate (n-BuA) initiated by an alkyl halide in the absence of any activator (e.g., Lewis acid) at 85 °C. The molecular weight distribution of the poly(meth)acrylates is narrow (Mw/Mn = 1.1−1.4). However, some side reactions (more likely coupling reactions) are observed at high monomer conversions in the case of n-BuA. An excess of PPh3 has proved to increase the polymerization rate of MMA while preserving the control of the molecular parameters. When the catalyst/initiator molar ratio is too small (e.g., 0.05), the polymerization rate decreases, the polydispersity increases, and the initiation is less efficient. α-Acid and α-hydroxyl end groups have been successfully attached to the chains by using functional initiators, such as 2-bromo-2-methylpropionic acid and 2,2‘,2‘ ‘-tribromoethanol. Reactivity ratios for the MMA/n-BuA comonomer pair have been measured and found to be close to the values observed for a conventional free-radical polymerization. Diethyl meso-2,5-dibromoadipate has been used as a difunctional initiator for the n-BuA polymerization, leading to α,ω-bromo-poly(n-BuA) of narrow molecular weight distribution. Finally, the thermal stability of PMMA is consistent with the lack of termination reactions, while Tg is as high as 125 °C. [less ▲]

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See detailRecent achievements in anionic polymerization of (meth)acrylates
Jérôme, Robert ULg; Teyssié, Philippe; Vuillemin, Bruno et al

in Journal of Polymer Science. Part A, Polymer Chemistry (1999), 37(1), 1-10

The constant progress of the anionic polymerization of (meth)acrylates is discussed from both the fundamental and practical points of view. A special attention is paid to the improved macromolecular ... [more ▼]

The constant progress of the anionic polymerization of (meth)acrylates is discussed from both the fundamental and practical points of view. A special attention is paid to the improved macromolecular engineering of (meth)acrylate-based (co)polymers. The resulting most important materials and the scaling-up process needed for their production are also emphasized. The recent developments witness for the healthy state of the anionic polymerization of these polar monomers. [less ▲]

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See detailNew initiator system for the anionic polymerization of (meth)acrylates in toluene. IV. Random copolymerization of (meth)acrylates in toluene initiated by s-Buli ligated by lithium silanolates
Zune, Catherine; Zundel, Thomas; Dubois, Philippe ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (1999), 37(14), 2525-2535

Copolymerization of binary mixtures of alkyl (meth)acrylates has been initiated in toluene by a mixed complex of lithium silanolate (s-BuMe2SiOLi) and s-BuLi (molar ratio > 21) formed in situ by reaction ... [more ▼]

Copolymerization of binary mixtures of alkyl (meth)acrylates has been initiated in toluene by a mixed complex of lithium silanolate (s-BuMe2SiOLi) and s-BuLi (molar ratio > 21) formed in situ by reaction of s-BuLi with hexamethylcyclotrisiloxane (D3). Fully acrylate and methacrylate copolymers, i.e., poly(methyl acrylate-co-n-butyl acrylate), poly(methyl methacrylate-co-ethyl methacrylate), poly(methyl methacrylate-co-n-butyl methacrylate), poly(methyl methacrylate-co-n-butyl methacrylate), poly(isobornyl methacrylate-co-n-butyl methacrylate), poly(isobornyl methacrylate-co-n-butyl methacrylate) of a rather narrow molecular weight distribution have been synthesized. However, copolymerization of alkyl acrylate and methyl methacrylate pairs has completely failed, leading to the selective formation of homopoly(acrylate). As result of the isotactic stereoregulation of the alkyl methacrylate polymerization by the s-BuLi/s-BuMe2SiOLi initiator, highly isotactic random and block copolymers of (alkyl) methacrylates have been prepared and their thermal behavior analyzed. The structure of isotactic poly(ethyl methacrylate-co-methyl methacrylate) copolymers has been analyzed in more detail by Nuclear Magnetic Resonance (NMR). [less ▲]

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See detailElectrografting of acrylic and methacrylic monomers onto metals: influence of the relative polarity and donor-acceptor properties of the monomer and the solvent
Baute, Noëlle; Teyssié, Philippe; Martinot, Lucien et al

in European Journal of Inorganic Chemistry (1998), 1998(11), 1711-1720

The possibility of grafting a series of alkyl polyacrylates and polymethacrylates onto a nickel cathode by electropoly-merization of the parent monomers has been investigated and has emphasized the ... [more ▼]

The possibility of grafting a series of alkyl polyacrylates and polymethacrylates onto a nickel cathode by electropoly-merization of the parent monomers has been investigated and has emphasized the critical importance of the solvent used. Indeed, the intensity of the inhibition peak, which is the electrochemical mark of the cathode passivation as result of the polymer grafting, clearly depends on both the polarity and the donor-acceptor properties of the solvent. The Gutmann concept is used to account for these experimental results. An increase in the donicity of the solvent used for the electrochemical medium has allowed, for the very first time, several polyacrylates and polymethacrylates [such as poly(ethyl acrylate), poly(methyl methacrylate), and poly(2-trimethylsilyloxyethyl methacrylate)] to be electrografted onto Ni. This observation is consistent with a competition process between the monomer and the solvent for being adsorbed on the cathode and amassing in its very close vicinity. The outcome of this competition is controlled by the relative polarity (in case of low donicity) and the relative donor-acceptor properties (when the difference is high enough) of the monomer/solvent pair, and by the monomer concentration (in case of weak competition). A semiquantitative relationship has also been observed between the monomer ability to be electrografted and the electron-accepting character of the vinyl β-carbon atom as measured by 13C NMR. [less ▲]

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See detailInvestigation of methyl methacrylate and vinyl acetate polymerization promoted by Al(iBu)3/2,2'-bipyridine and Al(iBu)3/2,2'-bipyridine/TEMPO complexes
Granel, Claude; Jérôme, Robert ULg; Teyssié, Philippe et al

in Macromolecules (1998), 31(21), 7133-7141

Results of methyl methacrylate (MMA) and vinyl acetate (VOAc) polymerization using the Al(iBu)3/2,2‘-bipyridine/TEMPO initiating system at room temperature failed to confirm the “living” radical mechanism ... [more ▼]

Results of methyl methacrylate (MMA) and vinyl acetate (VOAc) polymerization using the Al(iBu)3/2,2‘-bipyridine/TEMPO initiating system at room temperature failed to confirm the “living” radical mechanism reported earlier. Several species apparently propagate without control in a normal free radical process and only above a critical initiator concentration. No evidence was found for the penta- and hexacoordinated aluminum species previously suggested, but high conversion to an alkoxyamine was observed. Additionally, mixing Al(iBu)3 and BIPY promotes a variety of reactions involving alkyl and hydride transfers to the aromatic rings forming reduced BIPY products, along with a persistent organoaluminum radical. All these results illustrate that the process is considerably more complicated than postulated before. Conversely, at −78 °C, a single active species excluding the participation of TEMPO has been put in evidence, displaying some “living” characteristics. Several experiments support its anionic nature, as previously suggested by Ikeda. [less ▲]

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See detail4-Methoxypyridine N-Oxide: a new regulator for the controlled free radical polymerization of methyl methacrylate
Detrembleur, Christophe ULg; Lecomte, Philippe ULg; Caille, Jean-Raphaël et al

in Macromolecules (1998), 31(20), 7115-7117

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See detailDiffusive radical entry as the rate-determining step in amphiphilic block polyelectrolyte mediated emulsion polymerization
Leemans, Luc; Jérôme, Robert ULg; Teyssié, Philippe

in Macromolecules (1998), 31(17), 5565-5571

The amphiphilic water soluble block polyelectrolytes PMMA-b-SPGMA and PMMA-b-QPDMAEMA are efficient surfactants for the radical emulsion polymerization. Negatively charged, neutral, and positively charged ... [more ▼]

The amphiphilic water soluble block polyelectrolytes PMMA-b-SPGMA and PMMA-b-QPDMAEMA are efficient surfactants for the radical emulsion polymerization. Negatively charged, neutral, and positively charged entering radicals were used in combination with polyanionically and polycationically tailored PMMA latex particles. It was shown that the rate of polymerization was very high for systems wherein the entering radical species had an electrical charge sign identical with that of the polyelectrolyte corona around the latex particle. PMMA-b-SPGMA turned out to be 4 times as efficient as compared to SDS emulsified MMA polymerization at 0.6 wt %. Systems wherein polyelectrolyte block and entering radical were of opposite sign displayed strongly reduced polymerization rates. When the polyelectrolyte barrier became thick enough, as in the case of a Mn = 26 000 PMMA-b-QPDMAEMA, no more polymerization was observed. The observed polymerization rate effects are discussed in terms of repulsion of equal charge radicals, leading to enhanced mobility and counterion mobility restriction of the radicals of opposite sign to the polyelectrolyte block. In the latter case, this slowed counterion diffusion of radicals of opposite sign leads to premature aqueous phase termination of free radicals and consequently low flux of entering radicals with low rates of polymerization. The experimental results obtained are consistent with the theoretically predicted case, where the “control by aqueous phase growth” theory for the entry of free radicals in latex particles is invalid. [less ▲]

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See detailNew ligands for the living high-molecular-weight anionic (co)polymerization of acrylates in toluene at 0°C.1,2 3. Ligation of sec-butyllithium by lithium silanolates
Zundel, Thomas; Teyssié, Philippe; Jérôme, Robert ULg

in Macromolecules (1998), 31(17), 5577-5581

sec-Butyllithium combined with a new family of ligands, (i.e., lithium silanolates), has been used to initiate the ligated anionic polymerization of n-butyl acrylate (BuA) in toluene at low temperature ... [more ▼]

sec-Butyllithium combined with a new family of ligands, (i.e., lithium silanolates), has been used to initiate the ligated anionic polymerization of n-butyl acrylate (BuA) in toluene at low temperature. Compared to other μ-ligands, sBuMe2SiOLi is a more efficient stabilizer of the active centers. Thus, under selectively chosen reaction conditions, the polymerization proceeds quantitatively at −40 °C, producing a high-molecular-weight polymer with narrow-molecular-weight distribution (Mw/Mn < 1.2). When the copolymerization of BuA is initiated by a living {PMMALi, 5·sBuDLi} in toluene at −78 °C, the experimental data agree with a well-controlled block copolymerization reaction, since the final molecular-weight distribution is very narrow (Mw/Mn ≤ 1.1) and the polymerization efficiency very high. [less ▲]

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See detailLiving anionic polymerization of (meth)acrylic esters : new mechanistic concepts and resulting materials
Teyssié, Philippe; Baran, Janusz; Dubois, Philippe ULg et al

in Macromolecular Symposia (1998), 132

As an illustration of the frantic development of (meth)acrylic esters anionic polymerization during the last decade, three significant breakthroughs will be presented and analyzed: - extension of the LAP ... [more ▼]

As an illustration of the frantic development of (meth)acrylic esters anionic polymerization during the last decade, three significant breakthroughs will be presented and analyzed: - extension of the LAP (ligated anionic polymerization) concept to the practical synthesis of both high iso- or syndio high MW PMMA; - the production of "perfect" hydrocarbon gels from tailored PMMA-polybutadiene-PMMA triblock copolymers; - the use of reactivity "boosters" allowing to climb back up the nucleophilic reactivity scale, i.e. initiating styrene, dienes and (meth)acrylates polymerization with alcoholates and silanolates. [less ▲]

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See detailNew ligands for the living isotactic anionic polymerization of methyl methacrylate in toluene at 0°C. 2. 7Li NMR analysis of sec-butyllithium ligated by lithium silanolates
Zundel, Thomas; Zune, Catherine; Teyssié, Philippe et al

in Macromolecules (1998), 31(13), 4089-4092

The mixed associated species {xsBuLi, (y − x)sBuMe2SiOLi} formed by reaction of sec-Butyllithium (sBuLi) with octamethylcyclotetrasiloxane (Me2SiO)4 in toluene have been used to initiate the anionic ... [more ▼]

The mixed associated species {xsBuLi, (y − x)sBuMe2SiOLi} formed by reaction of sec-Butyllithium (sBuLi) with octamethylcyclotetrasiloxane (Me2SiO)4 in toluene have been used to initiate the anionic polymerization of methyl methacrylate (MMA) in that solvent at 0 °C. The active species generated by this new type of initiator have been characterized by 7Li NMR at 0 °C. The 7Li NMR spectra of sBuLi and sBuMe2SiOLi mixtures in toluene show that only one single type of {sBuLi, 5sBuMe2SiOLi} mixed species prevails at [sBuMe2SiOLi]/[sBuLi] molar ratios higher than ca. 21, as result of a large excess of {6sBuMe2SiOLi} species. The 7Li NMR has also concluded to the formation of {PMMALi, 5sBuMe2SiOLi} species upon the addition of MMA to that initiator solution, supporting the theory that only one type of ionic species is active during the MMA conversion. These active centers are stable for at least 1 h at 0 °C as confirmed by 7Li NMR. [less ▲]

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See detailProcess for radical controlled polymerization or copolymerization of (meth)acryl and vinyl monomers and thus prepared (co)polymers
Lecomte, Philippe ULg; Dubois, Philippe; Jérôme, Robert ULg et al

Patent (1998)

This process is characterized by the fact that at least one of the said monomers is polymerized or copolymerized in bulk, solution, emulsion or suspension, at a temperature that can be as low as 0 DEG C ... [more ▼]

This process is characterized by the fact that at least one of the said monomers is polymerized or copolymerized in bulk, solution, emulsion or suspension, at a temperature that can be as low as 0 DEG C., in the presence of an initiation system including: at least one compound generating radicals, other than bromofluorene, and at least one catalyst consisting of a complex of palladium in the 0 oxidation state, denoted by the following formula (I): Pd(0)L1L2L3L4 in which each of L1, L2, L3 and L4, which are identical or different, denotes a ligand which may be a chiral ligand, which is chosen from PRR'R'', P(OR)(OR')(OR''), NRR'R'', ORR', SRR', SeRR', AsRR'R'', SbRR'R'', where each of R, R' and R'' independently denotes a C1-C14 alkyl group, optionally substituted, or an optionally substituted aromatic group, it being possible for at least two of these ligands to be joined to one another by one or more divalent radicals. [less ▲]

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See detailMethod of free radical polymerization of copolymerization of (meth)acrylic and vinyl monomers under control and (co)polymer produced thereby
Lecomte, Philippe ULg; Dubois, Philippe; Jérôme, Robert ULg et al

Patent (1998)

PROBLEM TO BE SOLVED: To obtain a (co)polymer excellent in resistance to thermal decomposition by polymerizing or copolymerizing a monomer or monomers in the presence of an initiation system contg. a free ... [more ▼]

PROBLEM TO BE SOLVED: To obtain a (co)polymer excellent in resistance to thermal decomposition by polymerizing or copolymerizing a monomer or monomers in the presence of an initiation system contg. a free-radical generator other than a bromoolefin and a catalyst comprising a Pd complex having an oxidation number of 0 and represented by a specific formula. SOLUTION: A Pd salt (e.g. Pd acetate), a ligand (e.g. triphenylphosphine), and a solvent (e.g. toluene) are charged into a reactor to form a Pd complex having an oxidation number of 0 and represented by the formula: Pd(0)L<1> L<2> L<3> L<4> [wherein L<1> to L<4> are each a ligand such as PRR'R'' (wherein R, R', and R'' are each 1-14C alkyl, etc.)]. Then, a monomer (e.g. methyl methacrylate) is added to the reactor followed by the addition of a free-radical generator (e.g. CCl4 ) in a molar ratio of Pd to the generator of 0.01-100.; The contents in the reactor are heated to 40-90 deg.C and stirred for a certain time to conduct the polymn. The reaction mixture is diluted with toluene, etc., filtered, and condensed under a reduced pressure. The resultant polymer soln. is poured into methanol, etc., and the resultant precipitate is filtered, washed, and dried to give a polymer having a number average mol.wt. of 400-10,000,000g/mol and a polydispersity lower than 2. [less ▲]

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See detailClimbing back up the nucleophilic reactivity scale. Use of cyclosila derivatives as reactivity boosters in anionic polymerization
Zundel, Thomas; Baran, Janusz; Mazurek, Mieczyslaw et al

in Macromolecules (1998), 31(9), 2724-2730

It has been well-known for a very long time that, for anionic homo-polymerization or sequential copolymerization to occur, it is mandatory that the relative nucleophilic reactivity of the initiating ... [more ▼]

It has been well-known for a very long time that, for anionic homo-polymerization or sequential copolymerization to occur, it is mandatory that the relative nucleophilic reactivity of the initiating species be equal to or larger than the one of the (co)monomer. However, the results described in this paper demonstrate that such a classic rule can be circumvented in some cases. Indeed, it is reported for the first time that potassium trimethylsilanolate, and “living” potassium poly(ethylene oxide), both of which are unable to initiate styrene or methyl methacrylate (MMA) polymerization, can be converted from oxyanionic active ends to silyl anionic ones by reacting with cyclic disila derivatives, so allowing the homopolymerization and sequential (co)polymerization of styrene or MMA to proceed in a controlled manner. [less ▲]

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