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

Abstract

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.

Experimental and theoretical study of the reaction locus during the dispersion polymerization of methyl methacrylate in a nonpolar hydrocarbon solvent at low temperature

“…Except for k I and k fs , all the other kinetic parameters were adopted from literature, as indicated in Table 6 (see Refs. [53–61]). The overall initiation rate constant k I was adjusted to fit the measured monomer conversion of Experiment A (see Fig.…”

Following the Evolution of Ru/Activated Carbon Catalysts during the Decomposition–Reduction of the Ru(NO)(NO3)3 Precursor

“…A model was developed to successfully predict conversion data to high conversion levels. In a related study, Fenouillot et al9 investigated bulk MMA homopolymerization over the same temperature range in the presence of a chain transfer agent. BA/MMA bulk reactivity ratios were estimated over an extended temperature range (60–140 °C) by McManus et al10 In a follow‐up study, Hakim et al11 reported BA/MMA reactivity ratios over the same temperature range for solution copolymerizations in 30 and 50 wt.‐% toluene.…”

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

“…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.…”

“…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%.…”

“…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.…”