Kinetic and ESR studies on the radical polymerization of α‐n‐(α′‐methylbenzyl) β‐ethyl itaconamates derived from racemic and (s)‐α‐methylbenzylamines

Sato, Tsuneyuki; Tada, Shin‐Ichi; Seno, Makiko; Hirano, Tomohiro

doi:10.1002/1099-0518(20001115)38:22<4137::aid-pola140>3.3.co;2-t

Cited by 1 publication

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“…As reported previously,2 RS ‐MBEI showed a considerably higher R p in benzene than in MeOH, and R p of the RS monomer was somewhat higher than that of the S ‐monomer in both solvents. Figure 3 compares the polymerization results of RS ‐EMBI and S ‐EMBI in MeOH and benzene at 60 °C, for which the concentrations of the monomers and MAIB were 1.28 and 5.00 × 10 −2 mol/L.…”

Section: Resultssupporting

confidence: 85%

“…The results are summarized in Table 2. The k p values ranged from 0.42 to 1.32 L/mol s, depending on the monomer concentration and temperature (40–60 °C) used, and were fairly higher than those of MBEI (0.3–0.75 L/mol s) reported previously 2. However, they were much lower than the values of St (341 L/mol s at 60 °C)7 and MMA (834 L/mol s at 60 °C)8 as common monomers because of the steric effects due to bulky substituents of the EMBI monomers: The k p value increased with increasing monomer concentration for both the RS ‐ and S ‐monomers.…”

Section: Resultsmentioning

confidence: 70%

“…Although these tendencies are similar to those of conventional radical polymerizations, the dependencies on the concentrations of the monomer and initiator were much smaller than expected, suggesting chain transfer to the monomer. The molecular weights of poly( RS ‐EMBI) and poly( S ‐EMBI) were fairly higher than that ( M n = 1500–2000) of poly( RS ‐MBEI) prepared under corresponding polymerization conditions in MeOH 2…”

Section: Resultsmentioning

confidence: 87%

“…Similarly to the radical polymerizations of RS ‐MBEI and S ‐MBEI,2 the polymerization systems of RS ‐EMBI and S ‐EMBI with MAIB involved ESR‐observable propagating polymer radicals under the actual polymerization conditions. Figure 5 presents ESR spectra of the polymerization systems of RS ‐EMBI and S ‐EMBI observed at 60 °C in MeOH, for which the concentrations of the monomers and MAIB were 1.28 and 5.00 × 10 −2 mol/L.…”

Section: Resultsmentioning

confidence: 99%

“…In a previous article,2 we investigated kinetically the radical polymerization of α‐ N ‐(α′‐methylbenzyl) β‐ethyl itaconamates derived from ( RS )‐(racemic) and ( S )‐α‐methylbenzylamines ( RS ‐MBEI and S ‐MBEI) by means of electron spin resonance (ESR) and found that RS ‐MBEI showed somewhat higher homopolymerizability than S ‐MBEI and that the propagation rate constant ( k p ) of the former at 60 °C in benzene was 1.5 times that of latter.…”

Section: Introductionmentioning

confidence: 99%

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Elementary reaction analysis of the radical polymerization of α‐ethyl β‐N‐(α′‐methylbenzyl)itaconamates carrying (RS)‐ and (S)‐α‐methylbenzylaminocarbonyl groups

Sato¹,

Hashimoto²,

Seno³

et al. 2003

J. Polym. Sci. A Polym. Chem.

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The polymerizations of ␣-ethyl ␤-N-(␣Ј-methylbenzyl)itaconamates carrying (RS)-and (S)-␣-methylbenzylaminocarbonyl groups (RS-EMBI and S-EMBI) with dimethyl 2,2Ј-azobisisobutyrate (MAIB) were studied in methanol (MeOH) and in benzene kinetically and with electron spin resonance (ESR) spectroscopy. The initial polymerization rate (R p ) at 60°C was given byThe rate constants of initiation (k d f), propagation (k p ), and termination (k t ) as elementary reactions were estimated by ESR, where k d is the rate constant of MAIB decomposition and f is the initiator efficiency. The k p values of RS-EMBI (0.50 -1.27 L/mol s) and S-EMBI (0.42-1.32 L/mol s) in MeOH increased with increasing monomer concentrations, whereas the k t values (0.20 -7.78 ϫ 10 5 L/mol s for RS-EMBI and 0.18 -6.27 ϫ 10 5 L/mol s for S-EMBI) decreased with increasing monomer concentrations. Such relations of R p with k p and k t were responsible for the unusually high dependence of R p on the monomer concentration. The activation energies of the elementary reactions were also determined from the values of k d f, k p , and k t at different temperatures. R p and k p of RS-EMBI and S-EMBI in benzene were considerably higher than those in MeOH. R p of RS-EMBI was somewhat higher than that of S-EMBI in both MeOH and benzene. Such effects of the kinds of solvents and monomers on R p were explicable in terms of the different monomer associations, as analyzed by 1 H NMR. The copolymerization of RS-EMBI with styrene was examined at 60°C in benzene.

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Section: Resultssupporting

confidence: 85%