A New Difunctional Anionic Initiator

Foss, R. P.; Jacobson, H. W.; Sharkey, W. H.

doi:10.1021/ma60056a014

Cited by 52 publications

(19 citation statements)

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“…In the case of pure m -DVB in a hydrocarbon medium, the rate constant of the first addition, k 1 , is comparable to that of the second addition, k 2 . − The competitive reaction rates for the monoadduct and diadduct formation should lead to randomization of the process. In other words, the initiator sec -BuLi can react with two double bonds of DVB to form dianion B 2 * (Scheme ) leaving unreacted m -DVB (A 2 ).…”

Section: Resultsmentioning

confidence: 99%

Hyperbranched and Hyperstar Polybutadienes via Anionic Self-Condensing Vinyl Copolymerization

et al. 2021

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We synthesized highly branched polybutadienes by anionic self-condensing vinyl copolymerization (ASCVCP) of a butyllithium/divinylbenzene (DVB)-based initiator monomer (inimer) and butadiene. The molecular structure of polybutadienes was evaluated by SEC with MALLS and viscosity detection. SEC/viscosity measurements confirmed the branched structure of the obtained polymers. Examination of polymerization of two isomers of divinylbenzene, i.e., para-and meta-DVB, revealed differences in the mechanism. MALDI-ToF mass spectrometric analysis in the case of p-divinylbenzene indicates macroinimer formation as the first step, followed by condensation of the macroinimers into a highly branched polymer with narrowly distributed polybutadiene segments. The living nature of the polymerization allowed further amino-functionalization of the hyperbranched polybutadienes or subsequent growth of (meth)acrylate arms leading to hyperstar molecules. The reactivity of the primary amino groups in the aminofunctionalized copolymers was used in the grafting-onto reaction, i.e., amide formation with ω-carboxy-poly(N-isopropylacrylamide), leading to another type of hyperstar. To the best of our knowledge, these are the first examples of hyperstars with a polybutadiene copolymer core described to date.

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Section: Resultsmentioning

confidence: 99%

Hyperbranched and Hyperstar Polybutadienes via Anionic Self-Condensing Vinyl Copolymerization

et al. 2021

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“…Morton et al studied the effect of THF on the production of polystyrilithium in benzene and reported the acceleration of the reaction rates when THF, diethyl ether and triethylamine were added to the reaction system, even in small concentrations (0.004 M), although a point of maximum reaction rate would be eventually observed, as also reported by Hofmans and Beylen . Foss et al studied the reaction between sec‐BuLi and m‐diisopropenylbenzene in the presence of triethylamine (molar ratio of 0.1:1 in respect to Li) and reported the formation of multifunctional initiators with functionality greater than 2.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Evaluation of Multifunctional Anionic Initiators Based on n‐BuLi and Meta‐Diisopropenyl Benzene

Cazumbá

Tauchert²,

Nicolini³

et al. 2019

Macromolecular Symposia

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Multifunctional anionic initiators based on n‐BuLi and the diolefin m‐DIB (meta‐diisopropenylbenzene) were synthesized and stored at different temperatures, using different polar modifier contents and solvents. Solution styrene polymerizations were then used to evaluate the performances of the produced initiators. Based on the obtained results, it is shown that the best initiators were the ones prepared at 40 °C, using the DTHFP/BuLi molar feed ratio of 0.1 in cyclohexane. At these preparation conditions, the produced initiator has higher contents of multifunctional species and presents higher stability. The DTHFP/n‐BuLi ratio of 0.1 was shown to be the most appropriate because it minimizes the formation of oligomers and allows for suitable initiation of styrene polymerizations.

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“…27 The presence of aggregates and their dynamics with unimers govern the kinetics of initiation and propagation, with great impact on the molecular weight distribution. 27 The presence of aggregates and their dynamics with unimers govern the kinetics of initiation and propagation, with great impact on the molecular weight distribution.…”

Section: Introductionmentioning

confidence: 99%

Trifunctional organolithium initiator for living anionic polymerization in hydrocarbon solvents in the absence of polar additives

et al. 2016

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A novel hydrocarbon-soluble trifunctional organolithium initiator, with no polar-additive requirements, has been synthesized for use in anionic polymerization. The complete synthesis of the unsaturated tri-diphenylethylene compound, 4,4,4-(ethane-1,1,1-triyl)tris(((3-(1-phenylvinyl)benzyl)oxy)benzene) (I), is described and the efficiency of the new initiator is evaluated using 1 H NMR and Nano-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (NALDI-TOF MS). Activation of precursor I, was performed in situ using stoichiometric amounts of sec-BuLi in benzene. Three-arm polystyrene and polyisoprene stars with narrow molecular weight distributions were obtained in the case of relatively high total anion concentration, [sec-BuLi] 0 > 3.8 × 10 −3 mol L −1 (3 × [I] 0 ). At low total anion concentrations, uncontrolled molecular weight and broad/bimodal distributions were obtained, plausibly attributed to the presence of partially solvated aggregation dynamics complicating the propagation. The 'living' nature of the polymerization was confirmed by the sequential polymerization of styrene, and isoprene. The viscometric branching factor g' values of the final branched polymers were measured and compared to g' values of three-arm stars reported in the literature. † Electronic supplementary information (ESI) available. See

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A New Difunctional Anionic Initiator

Cited by 52 publications

References 0 publications

Hyperbranched and Hyperstar Polybutadienes via Anionic Self-Condensing Vinyl Copolymerization

Hyperbranched and Hyperstar Polybutadienes via Anionic Self-Condensing Vinyl Copolymerization

Synthesis and Evaluation of Multifunctional Anionic Initiators Based on n‐BuLi and Meta‐Diisopropenyl Benzene

Trifunctional organolithium initiator for living anionic polymerization in hydrocarbon solvents in the absence of polar additives

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