Batch polymerization of methyl methacrylate in mini/macroemulsions

Fontenot, Kevin; Schork, F. Joseph

doi:10.1002/app.1993.070490410

Cited by 80 publications

(66 citation statements)

References 16 publications

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“…If this is the case, the end of the nucleation should be about 20% conversion. This would be consistent with the results found by Chamberlain et al 10 and Fontenot et al, 28 while according to the number of particles obtained during the polymerization (Fig. 5), it seems that the end of nucleation in this system should be around 60% conversion.…”

Section: Particle Size and Its Distribution During Polymerizationsupporting

confidence: 89%

Miniemulsion copolymerization of styrene and butyl acrylate initiated by redox system at lower temperature: Reaction kinetics and evolution of particle-size distribution

Huang

Zhang

et al. 1999

J. Appl. Polym. Sci.

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ABSTRACT:The kinetics of the miniemulsion copolymerization of styrene (St) and butyl acrylate (BA) initiated by redox initiators, (NH 4 ) 2 S 2 O 8 /NaHSO 3 , at lower temperature (45°C) was studied. The polymerization rate in miniemulsion copolymerization is lower than that of the corresponding conventional emulsion copolymerization. In regard to the rate of polymerization, the initiator concentration plays a more important role in miniemulsion copolymerization than in conventional emulsion polymerization, while the surfactant concentration has a more important role in conventional emulsion polymerization than in miniemulsion polymerization. These are attributed to their different nucleation mechanisms, which are the same as those found in the miniemulsion polymerization carried out at higher temperatures. While by eliminating nucleation via micelle and ensuring against homogeneous nucleation, miniemulsion polymerization can be carried out by the sole nucleation mechanism-monomer droplet nucleation-at lower temperature. Because of this, the particles become narrower during the polymerization and, finally, monodisperse polymer particles are obtained. The result of the particle numbers indicated that a continuous nucleation will cease at about 60% conversion.

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Section: Particle Size and Its Distribution During Polymerizationsupporting

confidence: 89%

Miniemulsion copolymerization of styrene and butyl acrylate initiated by redox system at lower temperature: Reaction kinetics and evolution of particle-size distribution

Huang

Zhang

et al. 1999

J. Appl. Polym. Sci.

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“…Also, we can deduce that the nucleation period lasts to a monomer conversion of 40 -60%. It is coincident with the results observed by Miller et al 37 but discordant with the results observed by Fontenot and Schork 12 and Chamberlain et al 38 in the St miniemulsion polymerization initiated by KPS. They found that the nucleation period lasts to 10 -30% of the conversion.…”

Section: Polymerization Of Miniemulsionsupporting

confidence: 82%

Styrene miniemulsion polymerization stabilized by carboxylated polyurethane. I. Stability and polymerization

Zhang

Lee

Cheong

et al. 2003

J of Applied Polymer Sci

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Stability of the styrene miniemulsion costabilized by carboxylated polyurethane resins was investigated. The shelf life and the droplet size were measured. The results show that styrene miniemulsion costabilized by carboxylated polyurethane can be prepared although it is not as efficient as is hexadecane. The shelf life of the miniemulsion is influenced by the amount of the polyurethane and sodium dodecyl sulfate. The alkaline condition and the smaller molecular weight of the polyurethane are in favor of the stability of the miniemulsion. The polymerization results show that the hydrophility of the particle or droplet surface plays an important role in the process of the nucleation and polymerization. Homogeneous nucleation and droplet nucleation coexist in these systems. Nucleation lasts to 40 -60% conversion of the monomer in the acid medium, but it continues until the end of the polymerization in the alkaline medium.

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“…Furthermore, the value x ¼ 0:41 is much larger than 0.11 and 0.28 for the miniemulsion and emulsion polymerization of MMA. 42 On the contrary, x NMEP ¼ 0:14 is between 0.11 and 0.28. Delgado et al 3 found the opposite relationship in his copolymerization work with vinyl acetate and butyl acrylate.…”

Section: Colloidal and Molecular Weight Parametersmentioning

confidence: 99%

Microemulsion Polymerization of Butyl Acrylate under Ultrasound Irradiation

Capek

Janíčková

Donescu

et al. 2006

Polym J

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ABSTRACT:The microemulsion polymerization (MEP) of butyl acrylate (BA) stabilized by ionic emulsifier and initiated by oil-soluble dibenzoyl peroxide (DBP) or lauroyl peroxide (LPO) initiators have been studied under conventional (without ultrasound irradiation, CMEP) and ultrasonic (NMEP) conditions. The polymerization rate vs. conversion curve of the microemulsion polymerization of BA initiated by DBP was described by two nonstationary rate intervals. Four nonstationary rate intervals with two rate maxima appear in the microemulsion polymerization of BA initiated by LPO. The maximal rate of polymerization increases with temperature and the increase is much more pronounced under the conventional conditions. The overall activation energy is much larger under the conventional conditions (¼ 84 kJÁmol À1 ) than under the ultrasound (¼ 20 kJÁmol À1 ) conditions. The exit (desorption) rate constants The principle behind the formation of transparent or semitransparent microemulsions (fine emulsion with a droplet size 10-60 nm) is the very low interfacial tension caused by the penetration of coemulsifier into the droplet surface layer. Three-or four-component mixtures containing water, monomer, emulsifier and coemulsifier can form thermodynamically stable micellar solutions (microemulsions). The addition of coemulsifier increases the thermodynamic stability of micelles driving more emulsifier into micellar state, while on the other hand it can decrease the kinetic stability of micelles leading to faster formation and dissolution of micellar aggregates in solution. The thermodynamic stability of micelles is discussed in terms of how emulsifier distributes between the monomeric emulsifier and micellar state. The kinetic stability is discussed in terms of the average time of micellar aggregate. Cosolvents (coemulsifiers) are known to penetrate into micelles. The effect of such penetrating cosolvents can be discussed in terms of two aspects: an increase in distance between emulsifier groups and a decrease in the dielectric constant of micellar layer. This can explain the decrease of CMC as a result of dilution of micellar surface charge. 1 Furthermore, four-component mixtures (called miniemulsions with the droplet size 100-500 nm) containing water, monomer, emulsifier and hydrophobe form mostly kinetically stable emulsions. The principle behind the making of stable miniemulsions is the introduction of a hydrophobic compound into the monomer droplets to retard the diffusion of monomer out of the monomer droplets. In both microemulsion and miniemulsion, the principal locus of particle nucleation is the emulsified monomer droplet. In the former case the dependence of the rate vs. conversion is described by a curve with the maximum at ca. 20-40% conversion and the nucleation proceeds up to the final conversion. In the latter case, the particle nucleation is somewhat shortened up to ca. 30-50% and the dependence of the polymerization rate of styrene vs. conversion can be described by a curve with two maxima (four rate intervals...

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Batch polymerization of methyl methacrylate in mini/macroemulsions

Cited by 80 publications

References 16 publications

Miniemulsion copolymerization of styrene and butyl acrylate initiated by redox system at lower temperature: Reaction kinetics and evolution of particle-size distribution

Miniemulsion copolymerization of styrene and butyl acrylate initiated by redox system at lower temperature: Reaction kinetics and evolution of particle-size distribution

Styrene miniemulsion polymerization stabilized by carboxylated polyurethane. I. Stability and polymerization

Microemulsion Polymerization of Butyl Acrylate under Ultrasound Irradiation

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