Effect of reaction medium on the ionizing radiation‐initiated cationic copolymerization of styrene derivatives

Wood, Kenneth B.; Stannett, V.; Sigwalt, Pierre

doi:10.1002/pola.1995.080331708

Cited by 7 publications

(4 citation statements)

References 25 publications

(2 reference statements)

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“…Using AcClO 4 in different solvents (CH 2 Cl 2 or CH 2 Cl 2 /CCl 4 or C 6 H 5 NO 2 ) at 0 °C another publication reported r p MeSt = 1.8 − 3.2 . Sigwalt and co-workers reported r p MeSt = 2.49 and 6.64 in the copolymerization of p MeSt with St and p ClSt, respectively, in CH 2 Cl 2 at − 10 °C . Similar values ( r p MeSt = 2.5 and 6.6) were published by Wood et al Kennedy and co-workers found r p MeSt = 4.5 in the copolymerization of p MeSt and p ClSt in CCl 4 at 0 °C.…”

Section: Resultssupporting

confidence: 65%

“…12 Sigwalt and co-workers reported r pMeSt ) 2.49 and 6.64 in the copolymerization of pMeSt with St and pClSt, respectively, in CH 2 Cl 2 at -10 °C. 13 Similar values (r pMeSt ) 2.5 and 6.6) were published by Wood et al 14 Kennedy and coworkers 15 found r pMeSt ) 4.5 in the copolymerization of pMeSt and pClSt in CCl 4 at 0 °C. These values are in reasonable agreement with the value reported in this report.…”

Section: Comparison Of Reactivity Ratios With Publishedsupporting

confidence: 77%

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Structure−Reactivity Scales in Carbocationic Polymerizations

Kolishetti

Faust

2008

Macromolecules

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The polymerization of p-methylstyrene (pMeSt) in the presence of isobutylene (IB), styrene (St), p-chlorostyrene (pClSt), and 1,3-butadiene (BD) was carried out at -40 °C. By selecting CH 2 Cl 2 /methylcyclohexane (MeCHx) 50/50 (v/v) solvent mixture and the appropriate weak Lewis acid, SnBr 2 Cl 2 monoaddition of IB, St, pClSt, and BD followed by instantaneous termination was achieved, and the polymerizations stopped short of completion. The reactivity ratios, k p /k 12 , where k p is propagation rate constant and k 12 is the cross-propagation rate constant, were calculated on the basis of limiting conversions and limiting molecular weights. According to these values, pMeSt is 3.8 ( 0.5, 4.8 ( 1.1, 7.2 ( 1.6, and 100 ( 6 times more reactive than IB, St, pClSt, and BD respectively. Similar competition reactions between IB/BD, St/BD, and pClSt/BD in conjunction with TiCl 4 as Lewis acid yielded k p /k 12 ) 77 ( 5, 7.1 ( 1.0, and 3.2 ( 0.7, respectively. Using k p /k 12 and k p for pMeSt, St, and pClSt, the cross-propagation k 12 values were calculated to establish structure-reactivity scales. Similarly to our earlier observations, comparison of these values indicated that structural differences have a much larger effect on cation reactivity than on monomer reactivity.

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Section: Resultssupporting

confidence: 65%

Section: Comparison Of Reactivity Ratios With Publishedsupporting

confidence: 77%

Structure−Reactivity Scales in Carbocationic Polymerizations

Kolishetti

Faust

2008

Macromolecules

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“…As may be seen in Table 3, a few radiation initiated copolymerizations involving p ClSt do not obey the r 1 r 2 relationship in non polar solvents 41. This was explained by an intramolecular complexation of the more nucleophilic p ClSt + cation with the penultimate aromatic ring, which is absent in CH 2 Cl 2 (which competes for solvation) and for the less nucleophilic poly(St) + and poly( p MeSt) + carbocations.…”

Section: Reactivities Of Substituted Styrene Monomers In Copolymerizamentioning

confidence: 99%

Reactivities of carbocations and monomers in carbocationic polymerization and copolymerization

Sigwalt

Moreau

2010

J. Polym. Sci. A Polym. Chem.

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In carbocationic polymerization and copolymerization, a recent publication concluded that the substituent effect on carbocation reactivity is much larger than its effect on monomer reactivity, and this by a factor 106 in the case of the rate constant k12capp for p‐methylstyrene addition (monomer M2) on, respectively, poly(p‐methoxystyrene)± or poly(p‐methylstyrene)± (M 1±). This conclusion is disputed, as well as the assumption that the rate constants of capping (k12capp) obtained in deactivation reactions of poly(p‐methoxystyrene)± are identical with cross propagation rate constants in copolymerization (k12copol). It is shown that the large calculated k12capp are based on propagation constant values for p‐methylstyrene (k p± ≈ 109) obtained by the diffusion‐clock method. They are 104 times smaller as found for all styrenes, that is, between 104 and 105 when they are based on the ionic species concentrations. In such a case, the available data are still in agreement with an approximate compensation between the reactivities of a monomer and of the corresponding carbocation. It is also shown that copolymerization data for styrenes are not compatible with k p± values near to diffusion control, and that variations of log k12capp and log k12copol with the nucleophilicity parameter N of the monomers indicate a much lower selectivity of the monomers in the case of copolymerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2666–2680, 2010

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“…This was explained by an intramolecular complexation of the more nucleophilic carbocation pClSt þ with the penultimate aromatic ring, absent in CH 2 Cl 2 acting as a competitive solvating agent. [33] The mean values of r 1 and 1/r 2 for the three couples of these monomers ( pMeST/ St, St/pClSt and pMeSt/pClSt) in Table 4 have been calculated and show that pMeSt is 2.5 times more reactive than styrene, styrene about 2.5 times more reactive than pClSt and pMeSt about 6.5 times more reactive than pClSt.…”

Section: Relative Reactivities Of P-substituted Styrenes In Copolymermentioning

confidence: 99%

Can Propagation Reaction in Carbocationic Polymerization and Copolymerization of Styrene be Diffusion Controlled ?

Sigwalt

Moreau

2011

Macromolecular Symposia

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Summary:The reactivity ratios r 1 and r 2 in copolymerizations of styrene and parasubstituted styrenes, for which r 1 ¼ 1/r 2 , are in contradiction with diffusion control for their propagation reactions. The cross propagation rate constants k 12copol in copolymerization of styrene with p-chlorostyrene, p-methylstyrene and p-methoxystyrene have been shown to increase with their nucleophilicity parameter N. This is also not compatible with diffusion controlled cross propagation and propagation, but agrees with similar rate constants of propagation for these monomers. The capping rate constants k 12capp of reactions of poly( p-methylstyrene)AE and poly( pmethoxystyrene) AE with p-nucleophiles also increase with N, but with a much larger selectivity. This shows that k 12copol and k 12capp are not identical. The k ± p , from 10 9 to 6 10 9 L mol À1 s À1, obtained with p-chlorostyrene, styrene and p-methylstyrene by the Diffusion Clock (DC) method are not consistent with those derived from the ionic species concentration (ISC method) for indene, 2,4,6-trimethylstyrene and p-methoxystyrene of the order of 10 4 -10 5 L mol À1 s À1 , also measured for living polymerization. These last values are in agreement with those measured previously in nonliving systems, and with an approximate compensation between the reactivity of a monomer and that of the corresponding carbocation.

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Effect of reaction medium on the ionizing radiation‐initiated cationic copolymerization of styrene derivatives

Cited by 7 publications

References 25 publications

Structure−Reactivity Scales in Carbocationic Polymerizations

Structure−Reactivity Scales in Carbocationic Polymerizations

Reactivities of carbocations and monomers in carbocationic polymerization and copolymerization

Can Propagation Reaction in Carbocationic Polymerization and Copolymerization of Styrene be Diffusion Controlled ?

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