The termination reaction in radical polymerizations. II. Polymerizations of styrene at 60° and of methyl methacrylate at 0 and 60°, and the copolymerization of these monomers at 60°

Bevington, J. C.; Melville, H. W.; Taylor, R. P.

doi:10.1002/pol.1954.120147705

Cited by 276 publications

(49 citation statements)

References 6 publications

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“…The relative proportions were not very different than those observed for the free-radical polymerization methyl methacrylate (MMA). [22][23] It was clear that, although radical polymerization decreased the severity of the degradation of the PCAs, by itself it did not stop degradation completely.…”

Section: Degradation Of Free-radical Pcas Termination Modes and Degramentioning

confidence: 97%

“…The relative amounts of termination by coupling versus disproportionation for PCAs is not known; however, for other acrylic polymers such as poly(methyl methacrylate) (PMMA), disproportionation predominates. [22][23] One might anticipate that all three of the possible end-groups may be present in the radically initiated PCAs. Note that the structure at the lower right in the figure is identical to that produced by protonation of the chain end from anionic polymerization.…”

Section: Degradation Of Free-radical Pcas Termination Modes and Degramentioning

confidence: 99%

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Degradation and stabilization of polycyanoacrylates

Robello

Eldridge

Swanson

1999

J. Polym. Sci. A Polym. Chem.

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Section: Degradation Of Free-radical Pcas Termination Modes and Degramentioning

confidence: 97%

Section: Degradation Of Free-radical Pcas Termination Modes and Degramentioning

confidence: 99%

Degradation and stabilization of polycyanoacrylates

Robello

Eldridge

Swanson

1999

J. Polym. Sci. A Polym. Chem.

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“…However, this idea is not supported by the literature data. When Bevington et al 4 originally studied MMA polymerization to determine kdlk,, the reaction was carried out in 50% benzene and no solvent effects were noted (i.e., they predicted a PD = 2). We are thus puzzled by our observation.…”

Section: Resultsmentioning

confidence: 99%

Optimization of batch polymerization processes—narrowing the MWD. II. Experimental study

Louie

Soong

1985

J of Applied Polymer Sci

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SynopsisProgrammed solvent injection was previously proposed and analyzed in the first part of this twepaper series as a viable alternative for controlling the average molecular weight and narrowing the polydispersity of products from a free-radical polymerization process with an inherent tendency to exhibit strong gel and glass effects. Here, methyl methacrylate is chosen for experimental verification of this idea. The product molecular weight distribution is indeed narrowed.

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“…13 • 14 In this study, the equation proposed by North was used for the theoretical calculations. According to "the North model", 13 (15) Actual Calculations The number-average degree of polymerization and the copolymerization rate corresponding to the above combination CD were calculated by the Walling equation 12 conventionally.…”

Section: Rp=kp[p · ][M] =Kp{(2f'kd[i])/kt} 0 · 5 [M](7)mentioning

confidence: 99%

“…On the other hand, the termination in the homopolymerization of styrene (f 1 = 1) is known to be the coupling (p = 1 ). 15 The experimental value of the 2f'kd (1.60 x 10-7 s-1 ) was calculated from…”

Section: Rp=kp[p · ][M] =Kp{(2f'kd[i])/kt} 0 · 5 [M](7)mentioning

confidence: 99%

Penultimate Unit Effects in Free-Radical Copolymerization. Number-Average Degree of Polymerization and Copolymerization Rate in Styrene/Methyl Methacrylate/Toluene System

Ono

Teramachi

1995

Polym J

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ABSTRACT:Recently, Fukuda et al. showed from the measurements of absolute rate constants that in the free-radical copolymerization the propagation step obeys the penultimate model and the termination step is diffusion-controlled. Also Fukuda et al. proposed the "radical stabilization energy model" in the free-radical copolymerization. To examine this copolymerization model, relationships between feed monomer composition f 1 and number-average degree of polymerization x. and between f 1 and copolymerization rate RP were investigated for the copolymerization of styrene and methyl methacrylate in toluene at 40°C. The composition of the copolymer F1 was determined by 1 H NMR. The number-average molecular weight of the copolymer M. was measured to calculate x. by osmometry and size exclusion chromatography (SEC). By the so-called terminal model (the Mayo-Lewis model), the copolymer composition data was well described while the data of x. and RP were not described. Alternatively, the model proposed by Fukuda et al. described well the composition data, the x. data and the RP data. KEY WORDSDiffusion-Controlled Termination / Terminal Model Penultimate Model/ Number-Average Degree of Polymerization/ In the free-radical copolymerization of many binary systems, the relationship between the monomer feed composition / 1 and the copolymer composition F 1 have been described by the Mayo-Lewis equation 1 based on the terminal model.where r 1 arid r 2 are the monomer reactivity ratios. From this fact, the free-radical copolymerization mechanism had been believed to obey the terminal model. Paradoxes in this model, however, had been indicated so far. For example, the values of cross termination factor () are too large and dependent on the feed monomer composition. relationship between the monomer feed composition and the absolute rate constant of propagation (when the rate of copolymerization is described as analogous to that of homopolymerization). Moreover they showed that the propagation reaction of the freeradical copolymerization obeys the penultimate model and the termination reaction is diffusion-controlled. 2 -9 The penultimate model with 8 rate constants has 6 rate constant ratios, which are defined by them as Recently, Fukuda et al. showed that the Mayo-Lewis model fails to describe the 790 r1 =k111/k112, r'1 =k211/k212, S1 =k211/k111, r2=k222/k221(2) r~=k122/k121Sz =k122/k222 (4)

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The termination reaction in radical polymerizations. II. Polymerizations of styrene at 60° and of methyl methacrylate at 0 and 60°, and the copolymerization of these monomers at 60°

Cited by 276 publications

References 6 publications

Degradation and stabilization of polycyanoacrylates

Degradation and stabilization of polycyanoacrylates

Optimization of batch polymerization processes—narrowing the MWD. II. Experimental study

Penultimate Unit Effects in Free-Radical Copolymerization. Number-Average Degree of Polymerization and Copolymerization Rate in Styrene/Methyl Methacrylate/Toluene System

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