Thermal Polymerization of Methyl Methacrylate at High Temperature

Fenouillot, Françoise; Terrisse, J.; Rimlinger, T.

doi:10.3139/217.980154

Cited by 6 publications

(9 citation statements)

References 7 publications

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“…The mechanism of this kind of initiation is unsolved until now and still under investigation: Fenouillot et al [2] explained their observations by impurities that are introduced together with chain transfer agents or other reagents that decompose to radicals. Other authors [3,4] suspected peroxide containing species formed from monomer and physically dissolved molecular oxygen (in monomer and solvents) to be responsible for this Summary: Several researches have dealt with the thermal initiation of methyl methacrylate (MMA) in the past.…”

Section: Introductionmentioning

confidence: 99%

Thermal Initiation of MMA in High Temperature Radical Polymerizations

Nising

Meyer

Carloff³

et al. 2005

Macro Materials & Eng

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Summary: Several researches have dealt with the thermal initiation of methyl methacrylate (MMA) in the past. Some of them already discussed the presence of peroxide containing species that are formed from dissolved oxygen and the monomer itself as main reason for this initiation. However, a more detailed investigation as well as a kinetic description of this phenomenon is still due in literature. In this paper, the formation and decomposition of methyl methacrylate peroxides are described. MMA that has been in contact with air forms macromolecular peroxides at temperatures below 100 °C from physically dissolved oxygen. These peroxides have molecular weights of approximately 3 000–5 000 g · mol−1, depending on the temperature during formation. Above this temperature, these peroxides decompose quickly and initiate the radical polymerization. Depending on the reaction conditions, monomer conversions from 15 to 30% are obtained. In combination with additional initiators, the MMA peroxides provoke an acceleration of the reaction rate and can also lead to bimodal molecular weight distributions. An analytical method based on UV‐spectrophotometry was developed for the quantification of the peroxide content in the monomer. The kinetic rate constants for the formation were determined in batch experiments with purified, air‐saturated monomer to be kf,0 = 6.28 · 107 l2 · mol−2 · s and EA = 7.75 · 104 J · mol−1. The decomposition rate constants were determined from batch dead‐end polymerizations and found to be kd,0 = 4.73 · 107 l · mol−1 · s−1 and EA = 8.56 · 104 J · mol−1. magnified image

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Section: Introductionmentioning

confidence: 99%

Thermal Initiation of MMA in High Temperature Radical Polymerizations

Nising

Meyer

Carloff³

et al. 2005

Macro Materials & Eng

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“…When the temperature decreases the gel effect is more pronounced and the initiator is more effective as it is less burnt out, the result is a higher conversion. This trend was also observed in the batch reactor 10, 11. These operating conditions are not comfortable because at low temperature and consequently high conversion, the viscosity of the medium increases and it becomes difficult to maintain the agitation because of the limited torque of the motor.…”

Section: Resultsmentioning

confidence: 56%

“…The bulk polymerization of MMA is run at elevated temperature (120–180°C) and initiated by DTBP; BSH is used to control the molecular weight. We have detailed the kinetics of this reaction system in previous studies10, 11 showing that some particularities must be taken into account for above T g polymerization. The monomer used in the batch reactor to establish the kinetics11 and to run this continuous reactor is distillated with the same procedure, except that in the case of the continuous reactor, the monomer is stored and transported under an inert gas.…”

Section: Polymerization Mechanism and Kineticsmentioning

confidence: 99%

“…However, Corpart,7 Clouet,8 Fleury,9 and Fenouillot10, 11 in previous works have studied the specific features of the polymerization at high temperature. They have shown that at a temperature above 120°C, the thermal initiation and the initiation reaction by imputities cannot be neglected anymore, and depending on the purification method of the monomer can lead to conversions around 10–20%.…”

Section: Introductionmentioning

confidence: 99%

“…No solvent is used. The steady state behavior of the reactor is modeled based on our earlier study of the kinetic aspects of the reaction 10, 11. The experimental results obtained on the pilot reactor are compared with the predicted values.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study and simulation of the polymerization of methyl methacrylate at high temperature in a continuous reactor

Fenouillot¹,

Terrisse²,

Rimlinger³

2001

J. Appl. Polym. Sci.

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The bulk polymerization of MMA at high temperature (120–180°C) in a continuous pilot‐plant reactor has been studied. The polymerization is initiated by diterbutyle peroxide and the chain transfer agent is 1‐butanethiol. A simulation program has been developed to predict the steady state behavior of the reactor. The particular features of the kinetic at above‐Tg temperature are included in the model, especially the thermal initiation of the reation and the attenuation of the autoacceleration effect. For the flow and mixing model, the actual vessel cannot be approximated to a single ideal reactor because of its design and of the moderate agitation imposed by the high viscosity of the reacting fluid. A tanks in series model with a recycle stream between tanks is proposed to evaluate the backmixing caused by the special design of the agitator. The parameters of the model are determined with the help of the experimental residence time distribution measured on the reactor. The data collected on the actual reactor, i.e., operation, conversion, molecular weight, temperature, are compared to the calculated one. The agreement is satisfactory but the tendencies are slightly underestimated. The program is a tool to evaluate the effect of modifications of the design of the reactor or changes on the operation parameters like input rate, temperature, and agitation on its behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2038–2051, 2001

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Polymerization of methyl methacrylate at high temperature with 1-butanethiol as chain transfer agent

Fenouillot¹,

Terrisse²,

Rimlinger³

1999

J. Appl. Polym. Sci.

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ABSTRACT:The free-radical polymerization of methyl methacrylate (MMA) at high temperature (120 to 180°C) has been studied in the presence of di-tertiobutyle peroxide as an initiator and 1-butanethiol as a chain transfer agent. No solvent was used, and the polymerization was run to high monomer conversion. Based on the experimental data collected with a dilatometric reactor, the features of the reaction have been pointed out. Working at high temperature with a chain transfer agent proved efficient to reduce the intensity of the gel effect and control the molecular weight obtained. At a temperature up to 170°C, however, the burn-out of the initiator limits the final conversion, and the increase of the polymerization rate during the gel effect has been more difficult to detect and quantify. An empirical expression of the termination rate constant has been adopted to describe the autoacceleration and predict the conversion versus time curves and the average molecular weight of the polymer obtained. The mathematical model includes two adjustable parameters that have been determined as a function of the temperature and the initial concentration of the chain transfer agent. The agreement between the predicted and experimental data on conversion and molecular weight was good, while the polydispersity index was often underestimated.

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Thermal Polymerization of Methyl Methacrylate at High Temperature

Cited by 6 publications

References 7 publications

Thermal Initiation of MMA in High Temperature Radical Polymerizations

Thermal Initiation of MMA in High Temperature Radical Polymerizations

Experimental study and simulation of the polymerization of methyl methacrylate at high temperature in a continuous reactor

Polymerization of methyl methacrylate at high temperature with 1-butanethiol as chain transfer agent

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