Kinetics of the styrene emulsion polymerization above cmc. II. Agitation effect on molecular weight

Ramírez, Jorge C.; Herrera‐Ordóñez, Jorge; Maldonado‐Textle, Hortensia

doi:10.1007/s00289-005-0354-9

Cited by 17 publications

(14 citation statements)

References 5 publications

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“…The number of latex particles in the system, N p , was determined from the monomer conversion and the particle size distribution, which is based on a knowledge of the total mass of polymer formed and the mass of polymer in each latex particle as described by Ramirez et al [18]:…”

Section: Parameters Evaluationmentioning

confidence: 99%

Kinetic study of styrene and methyl methacrylate emulsion polymerization induced by cumene hydroperoxide/tetraethylenepentamine

et al. 2015

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The redox initiator, cumene hydroperoxide/ tetraethylenepentamine (CHPO/TEPA), was used to initiate the emulsion polymerizations of styrene and methyl methacrylate (MMA). The hydrophobic CHPO acting as oxidizer would interact with the hydrophilic TEPA employed as the reducer at the particle-water interface where the vinyl monomer is present. The kinetics of the styrene and MMA polymerizations were studied under a temperature range of 30-70°C. The polymerization rate, the concentration of monomer in the particles, the average number of latex particles and the number of radicals per particle were investigated to evaluate the propagation rate constant during interval II of the polymerization. With increasing temperature, the number of latex particles increases while the monomer concentration in the particles slightly decreases. The observed number of radicals per particle, calculated from the number average volume of the particles and the relation between the entry rate coefficients of free radicals into the particles and the exit rate coefficients of free radicals from the particle, was found to be approximately 0.47 and 0.5 in case of styrene and MMA polymerization, respectively. The calculation shows that the propagation rate constant, k p = 6.84 × 10 7 e −37.65/RT and k p =3.4×10 7 e −31.05/RT L/mol s for styrene and MMA polymerizations over the temperature range studied, respectively.

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Section: Parameters Evaluationmentioning

confidence: 99%

Kinetic study of styrene and methyl methacrylate emulsion polymerization induced by cumene hydroperoxide/tetraethylenepentamine

et al. 2015

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“…According to Ramirez et al, 9 an additional interpretation can be given as well. The undesired effects of high agitation speed may be originated from the increment of frequency of the free radical re-entry to the polymer particles.…”

Section: Effect Of Agitationmentioning

confidence: 99%

“…5 In the previous literatures, the effects of different variables on emulsion polymerization have been studied. They covers variables such as agitation speed, 1,[6][7][8][9][10][11][12][13][14][15][16][17][18][19] initiator type and concentration, 1,2,[6][7][8]15,16,18,[20][21][22][23][24][25][26][27][28][29][30][31][32] emulsifier type and concentration, 8,18,20,21,24,25,[28][29][30][32][33][34][35][36]…”

Section: Introductionmentioning

confidence: 99%

Semibatch emulsion copolymerization of butyl acrylate and glycidyl methacrylate: Effect of operating variables

Bakhshi

Bouhendi

Zohuriaan‐Mehr

et al. 2010

J of Applied Polymer Sci

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Semibatch emulsion copolymerization was carried out to prepare poly(butyl acrylate-co-glycidyl methacrylate) latexes at 75 C, using potassium persulfate as an initiator, sodium dodecylbenzene sulfonate as an emulsifier and sodium bicarbonate as a buffer. The reaction was conducted in three stages; a further stage (called the steady stage, 2 h) was added to the traditionally stages (i.e., feed and seed stages) to improve considerably the monomer conversion. The monomer conversion and particle size distribution were studied by gravimetric and laser light scattering methods, respectively. The effects of variables such as agitation speed, emulsifier concentration, initiator concentration, feeding rate and comonomers ratio were fully investigated based on the monomer conversion-time profiles and the particle size distribution to find the optimized copolymerization conditions. Increasing the agitation speed had a negative effect on the monomer conversion, but reduced coagulation of polymer particles. Monomer conversion could be improved by increasing the initiator or emulsifier contents. Feeding rate increased the polymer particle size sharply; however, it showed no significant effect on conversion. The final conversions were as high as 97-99% and they were recognized to be independent of the comonomers ratios employed. Morphological studies by scanning electron microscopy showed nano-sized isolated particles which were partially aggregated.

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“…They can be distinguished into ionic and nonionic agents having hydrophilic groups and hydrophobic radicals. Carboxyl and sulfate compounds among others belong to the group of anionic surface‐active agents 5–8…”

Section: Introductionmentioning

confidence: 99%

Stability of nanoparticles during semibatch emulsion polymerization of butyl methacrylate, in the presence of methacrylic acid via RSM

Naderi¹,

Sharifi-Sanjani²,

Khayyat-Naderi³

et al. 2007

J of Applied Polymer Sci

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ABSTRACT:The size and stability of latex particles in the semibatch emulsion polymerization of butyl methacrylate (BMA), in the presence of 0-10% methacrylic acid (MAA), were investigated. Response surface methodology (RSM), as a design of experiment, was used to obtain a more systematic understanding of the role of emulsifier and MAA in the stability of the particles. The amount of coagulum can be greatly reduced by increasing the concentration of sodium lauryl sulfate (SLS) in the monomer emulsion feed (MEF) and initial reactor charge (IRC). On the other hand, increasing the concentration of SLS in the IRC can result in a decrease of the particles size. According to the experimental data, the yield of reaction can be improved with incorporation of MAA into the emulsion polymers. The size and morphology of particles were obtained by scanning electron microscopy (SEM). FTIR and titration were used to determine the percentage of MAA in the copolymer.

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Kinetics of the styrene emulsion polymerization above cmc. II. Agitation effect on molecular weight

Cited by 17 publications

References 5 publications

Kinetic study of styrene and methyl methacrylate emulsion polymerization induced by cumene hydroperoxide/tetraethylenepentamine

Kinetic study of styrene and methyl methacrylate emulsion polymerization induced by cumene hydroperoxide/tetraethylenepentamine

Semibatch emulsion copolymerization of butyl acrylate and glycidyl methacrylate: Effect of operating variables

Stability of nanoparticles during semibatch emulsion polymerization of butyl methacrylate, in the presence of methacrylic acid via RSM

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