Study of the isothermal bulk polymerization of methyl methacrylate by differential scanning calorimetry

Malavašič, T.; Vizovišek, I.; Lapanje, Savo; Može, Adolf

doi:10.1002/macp.1974.021750314

Cited by 39 publications

(10 citation statements)

References 9 publications

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“…Conversion at different reaction times were calculated from the area between the curve and the baseline, which was obtained by back extrapolation of the straight line, recorded after the end of the polymerization reaction [32,33]. The experimental heat of polymerization is with less than 10% consistent with the literature (Ϫ67.5 to Ϫ70 kJ mol Ϫ1 , [26]).…”

Section: Methodssupporting

confidence: 67%

Kinetic modeling of free radical polymerization of styrene initiated by the bifunctional initiator 2,5-dimethyl-2,5-bis(2-ethyl hexanoyl peroxy)hexane

Cavin

2000

Polymer

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This paper deals with the kinetic study of bulk free radical polymerization of styrene initiated with the commercial bifunctional initiator 2,5-dimethyl-2,5-bis(2-ethyl hexanoyl peroxy)hexane (Lupersol 256). The polymerization kinetics is investigated by DSC measurement for temperatures between 80 and 110ЊC and for initiator initial concentration from 0.115 up to 0.46 mol%. The experimental conversion and reaction rate are compared and discussed with the calculated values. For modeling the polymerization rate, a reaction scheme similar to the one given by Yoon and Choi (Polymer 1992;33(21):4582-4591) has been used and adapted. A detailed diffusional and semi-empirical model proposed by Chiu et al. (Macromolecules 1983;16(3):348-357) has been modified by Rouge (Etude de la polymérisation radicalaire du styrène initiée par un amorceur bifonctionnel dans un réacteur tubulaire à recyclage, Diploma work, DC, EPF, Lausanne, 1997) in order to describe these results. The model allows the description of the number molecular weight, but the polydispersity is underestimated for conversion higher than 70%. For temperature higher than 100ЊC, thermal initiation must be taken into account. The efficiency factor is found close to 1, but seems to decrease for temperatures above 100ЊC. ᭧

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Section: Methodssupporting

confidence: 67%

Kinetic modeling of free radical polymerization of styrene initiated by the bifunctional initiator 2,5-dimethyl-2,5-bis(2-ethyl hexanoyl peroxy)hexane

Cavin

2000

Polymer

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“…The polymerization enthalpies AHp (Table 1) have been calculated from the areas under the DSC curves, after correcting for the residual monomer content. The values of AHp are between -55 and -58 kJ/mol, similar to those for other methacrylic monomers [4][5][6][7][8]. No temperature dependence of the polymerization enthalpies in the temperature range 348-373 K has been observed.…”

Section: Resultsmentioning

confidence: 73%

“…The aim was to determine the influence of the size and the position of alkyl substituents in pendent aryl groups of the monomer molecule on kinetic parameters. The present investigation is an extension of this work using differential scanning calorimetry (DSC), which has proved to be convenient for studying the polymerization of vinyl monomers [3][4][5][6][7][8]. The rate of polymerization is determined directly, continuously and even in a gel or solid state [3].…”

Section: Introductionmentioning

confidence: 99%

Isothermal bulk polymerization ofp-alkylaryl methacrylates by DSC

Filipović

Petrovic-Dakov

Vrhovac

et al. 1992

Journal of Thermal Analysis

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The course and kinetics of free radical polymerization in bulk ofp-alkylphenyl methacrylates with AIBN initiator were studied by DSC, in the temperature range 348-373 K. The enthalpy of polymerization, the residual monomer content, as well as the overall reaction rate constants and the activation energies were determined. The similar values of the overall rate constants indicate that the relatively small alkyl substituents in p-position of the phenyl ring affect the polymerization rate to a very small, if any, extent.

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“…Two other phases of the polymerization, which can also be considered as the onset of the gel effect, can easily be obtained from the DSC curves. These are the deviation from linearity in the diagram for the first-order reaction with respect to monomer concentration [9] and the deviation from linearity in the conversion w time diagram. The values are given in Table 1.…”

Section: Resultsmentioning

confidence: 98%

Study of the polymerization of some methacrylic acid esters by differential scanning calorimetry

Malavašič

Osredkar

Anžur

et al. 1984

Journal of Thermal Analysis

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The strengths of the gel effect, and the monomer conversions at which the gel effect sets in for the polymerizations of some methacrylic acid esters, were determined at different temperatures from the courses of polymerization measured by differential scanning calorimetry. It was found that the strength of the gel effect is greatly influenced by the reaction temperature and the ester residue in the molecule of the monomer, whereas the "critical" conversion for individual monomers is practically independent of the reaction temperature in the measured interval, but is strongly dependent on the length of the ester residue.The isothermal radical polymerization of methacrylic acid esters, and especially of methyl methacrylate (MMA), have been studied by many authors. It is known that the classical free radical kinetics are valid only at low conversions, As the reaction proceeds, the concentration of the macromolecules and the viscosity of the reaction mixture increase. The chain termination rates are therefore diminished and the gel effect sets in [1]. There are some kinetic models describing the polymerization of MMA at high conversions [2][3][4][5][6][7]; these also try to establish the conversion at which the gel effect starts. In these works the already published data obtained by "classical" dilatometry were used for calculations [8]. In the oresent work differential scanning calorimetry was used to measure the course of the isothermal polymerization over the entire range of conversion and to determine the onset of the gel effect. ExperimentalThe radical polymerization of some methacrylic monomers was investigated isothermally at different temperatures with a Perkin-Elmer DSC-2 differential scanning calorimeter. As initiator, 2,2'-azoisobutyronitrile (AIBN) was used. The reaction mixtures were put into the calorimeter, which was set at the selected temperatures.

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Study of the isothermal bulk polymerization of methyl methacrylate by differential scanning calorimetry

Cited by 39 publications

References 9 publications

Kinetic modeling of free radical polymerization of styrene initiated by the bifunctional initiator 2,5-dimethyl-2,5-bis(2-ethyl hexanoyl peroxy)hexane

Kinetic modeling of free radical polymerization of styrene initiated by the bifunctional initiator 2,5-dimethyl-2,5-bis(2-ethyl hexanoyl peroxy)hexane

Isothermal bulk polymerization ofp-alkylaryl methacrylates by DSC

Study of the polymerization of some methacrylic acid esters by differential scanning calorimetry

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