Initiation of living polymerization of isobutyl vinyl ether by the ?H2O?/n-Bu4NTiCl5 system

Lubnin, Alexander V.; Kennedy, Joseph P.

doi:10.1007/bf00944814

Cited by 5 publications

(1 citation statement)

References 5 publications

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“…This should lead to the complete inhibition of polymerization at 100% salt added. However, further addition of up to 100% salt reduces the polymerization rate by only [20][21][22][23][24][25][26][27][28][29][30] %. This indicates that SnCL" may also ionize alkyl halides, although slightly less efficiently than SnCl4.…”

Section: Resultsmentioning

confidence: 99%

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

Lin¹,

Xiang²,

Matyjaszewski³

1993

Macromolecules

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The effect of tetrabutylammonium chloride on the kinetics and the molecular weight distribution in the cationic polymerization of styrene initiated by 1-phenylethyl chloride/SnCL was investigated. This "living" system resembles classic cationic systems but proceeds with a lower instantaneous concentration of active carbocations. The carbenium ions form covalent species reversibly. The fraction of unpaired carbocations can be suppressed by addition of salts with common anions. When molecular weights are low enough, the transfer reactions cannot be easily detected and polymers with low polydispersities are formed. For this system, the upper limit of the molecular weight control is in the range of Mn = 5000 at 20 °C. Polymerization rates decrease approximately 5 times in the presence of a small amount of salt ([saltJ/tSnCU < 0.1), remain fairly constant until [salt]/[SnCLi] == 1, and then rapidly decrease at ratios [salt]/[SnCLi] > 1. The changes in the structure of Lewis acid and anions were monitored by 119Sn NMR. One average signal was observed at low salt concentrations due to a rapid exchange between SnCLi and SnCl5-. At ratios [salt]/[SnCLi] > 1 very broad signals were found which were converted to a sharp signal of the SnCL2" anion at ratios [salt]/ [SnCLi > 2. The unusual kinetics and n9Sn-NMR data were explained by nearly equal ionization ability of SnCLi and the SnCl5~anion and by the formation of inactive oligomeric anions (Cl-[SnCls-] ") at ratios [salt]/[SnCLJ > 1.

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Section: Resultsmentioning

confidence: 99%

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

Lin¹,

Xiang²,

Matyjaszewski³

1993

Macromolecules

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Cationic Polymerization of Styrene Derivatives and Cyclopentadiene Catalyzed by B(C₆F₅)₃ in Aqueous Media: Comparison of Suspension, Emulsion and Dispersion Processes

Kostjuk

Ganachaud

Radchenko

et al. 2011

Macromolecular Symposia

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Summary: The cationic polymerization of styrene derivatives [p‐methoxystyrene (pMOS), p‐hydroxystyrene (pHS), styrene (St)] and cyclopentadiene (CPD) using B(C6F5)3‐based initiating systems in aqueous media is reported, focusing specifically on the influence of various additives (surfactant, solvent) on the control of the polymerization rate and molar masses. 1‐(4‐Methoxyphenyl)ethanol (1)/B(C6F5)3 system induced living dispersion (in solvent/water mixture, without surfactant) cationic polymerize‐tion of pMOS and pHS, affording polymers which Mns increased in direct proportion to monomer conversion (Mn ≤ 4500 g mol−1) and which exhibited rather narrow molecular weight distributions (Mw/Mn ≤ 1.5). Polymerization of St and CPD in suspension (in water without surfactant) proceeded uniquely through activation of the initiator followed by irreversible termination by water giving oligomers with Mn ≤ 2000 g mol−1 and Mw/Mn ≤ 2.0. Besides, pHS also polymerized in a living fashion under emulsion (in micellar aqueous solutions) conditions (Mn ≤ 4500 g mol−1; Mw/Mn ≤ 1.5) using either BRIJ®97 or hexa‐decyltrimethylammonium bromide (CTAB) as surfactants, whereas conventional non‐living cationic polymerization occurred with pMOS (using BRIJ®97 or CTAB as surfactants) and CPD (using dodecylbenzenesulfonic acid, DBSA).

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Living carbocationic polymerization of isobutyl vinyl ether and the synthesis of poly[isobutylene‐b‐(isobutyl vinyl ether)]

Lubnin

Kennedy

1993

J. Polym. Sci. A Polym. Chem.

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SYNOPSISThe MeCH (0-i-Bu) C1/TiC14/MeCONMe2 initiating system was found to induce the rapid living carbocationic polymerization ( LC@Pzn) of isobutyl vinyl ether ( IBuVE) at -100°C. Degradation by dealcoholation which usually accompanies the polymerization of alkyl vinyl ethers by strong Lewis acids is "frozen out" at this low temperature and poly (isobutyl vinyl ether)s (PIBuVEs) with theoretical molecular weights up to ca. 40,000 g/mol (calculated from the initiator/ monomer input) and narrow molecular weight distributions (&,/an I 1.2) are readily obtained. According to 13C-NMR spectroscopy, PIBuVEs prepared by living polymerization at -100°C are not stereoregular. The MeCH ( 0-i-Bu) C1/ TiC1, combination induces the rapid LC"Pzn of IBuVE even in the absence of N,N-dimethylacetamide (DMA). The addition of the common ion salt, n-Bu4NCl to the latter system retards the polymerization and meaningful kinetic information can be obtained.The kinetic findings have been explained in terms of TiC14 -IBuVE and TiCl, PIBuVE complexes. The HC1 (formal initiator) /TiCI,/DMA combination is the first initiating system that can be regarded to induce the LC"Pzn of both isobutylene (IB) and IBuVE. Polyisobutylene ( PIB ) -PIBuVE diblocks were prepared by sequential monomer addition in "one pot" by the 2-chloro-2,4,4-trimethylpentane ( TMP-C1) /TiCl,/DMA initiating system. Crossover efficiencies are, however, below 35% because the PIB@ + IBuVE + PIBb-PIBuVE@ crossover is slow. 0 1993 John Wiley & Sons, Inc.

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Initiation of living polymerization of isobutyl vinyl ether by the ?H2O?/n-Bu4NTiCl5 system

Cited by 5 publications

References 5 publications

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

Cationic Polymerization of Styrene Derivatives and Cyclopentadiene Catalyzed by B(C₆F₅)₃ in Aqueous Media: Comparison of Suspension, Emulsion and Dispersion Processes

Living carbocationic polymerization of isobutyl vinyl ether and the synthesis of poly[isobutylene‐b‐(isobutyl vinyl ether)]

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Initiation of living polymerization of isobutyl vinyl ether by the ?H2O?/n-Bu4NTiCl5 system

Cited by 5 publications

References 5 publications

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

"Living" cationic polymerization of styrene in the presence of tetrabutylammonium salts

Cationic Polymerization of Styrene Derivatives and Cyclopentadiene Catalyzed by B(C6F5)3 in Aqueous Media: Comparison of Suspension, Emulsion and Dispersion Processes

Living carbocationic polymerization of isobutyl vinyl ether and the synthesis of poly[isobutylene‐b‐(isobutyl vinyl ether)]

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Cationic Polymerization of Styrene Derivatives and Cyclopentadiene Catalyzed by B(C₆F₅)₃ in Aqueous Media: Comparison of Suspension, Emulsion and Dispersion Processes