Diffusional limitations in emulsion polymerization

Zubitur, Manuela; Mendoza, Juan J.; Cal, José C. de la; Asua, JoséM.

doi:10.1002/1521-3900(200002)150:1<13::aid-masy13>3.0.co;2-g

Cited by 11 publications

(13 citation statements)

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“…An empirical correlation that correlates [M] p with [M] w is: [11] (2)- (4). Note that Equation (4) does not hold in a real system for the whole range of particle sizes.…”

Section: Monomer Concentrationsmentioning

confidence: 99%

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Diffusion‐Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

Sajjadi

2004

Macromol. Rapid Commun.

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Summary: Particle formation and growth in the batch emulsion homo‐polymerisation of styrene and methyl methacrylate monomers under diffusion‐controlled conditions were studied. The polymerisations started with two stratified layers of a monomer and water containing an initiator and a surfactant, with the water layer being gently stirred. Because of limitations in monomer transport, the rate of particle growth was substantially reduced and as a result a large number of polymer particles formed.Schematic presentation of the highly diffusion‐controlled polymerisation.imageSchematic presentation of the highly diffusion‐controlled polymerisation.

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“…An empirical correlation that correlates [M] p with [M] w is: [11] (2)- (4). Note that Equation (4) does not hold in a real system for the whole range of particle sizes.…”

Section: Monomer Concentrationsmentioning

confidence: 99%

“…[3] At a low stirring speed, the rate of polymerisation is diffusion controlled. [2][3][4][5] This has been associated with a formation of a larger number of particles. [6][7][8] The effects of impeller speed and/or type on the rate of copolymerisation, molecular weights, [4,9] and particle size distribution [10] have been also reported.…”

Section: Introductionmentioning

confidence: 99%

Diffusion‐Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

Sajjadi

2004

Macromol. Rapid Commun.

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“…However, “effective” C X values are defined that assume equilibrium conditions in all phases. The mass transfer of a CTA between phases is affected by the stirring rate, the monomer‐droplets size, the particle size, and the CTA diffusivity 4, 5…”

Section: Introductionmentioning

confidence: 99%

Emulsion polymerization of styrene with Iso‐octyl‐3‐mercaptopropionate as chain transfer agent

Minari¹,

Vega²,

González‐Sierra³

et al. 2008

J of Applied Polymer Sci

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Four batch and unseeded emulsion polymerizations of styrene were investigated, which included isooctyl 3-mercaptopropionate (iOMP) as chain transfer agent (CTA). This compound was analyzed by 13 C NMR and GC/ MS, resulting in a mixture of over 10 isomers. Because of different reactivities of the CTA isomers, the produced polystyrenes presented broad and bimodal molecular weight distributions (MWDs). A mathematical model was adjusted to the measurements, and the measured MWDs were adequately predicted when assuming the CTA as a binary mixture of high but different reactivities.

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“…To the best of our knowledge, no study has ever been conducted to specifically investigate this issue. However, many researchers have investigated the use of CTAs (particularly the mercaptans) in emulsion polymerization in general 16–26. An important feature of emulsion polymerization systems utilizing mercaptan CTAs is that under some conditions the effectiveness of the CTA may be limited by its mass transfer from the monomer droplet, through the water phase, and into the polymer particle where it is needed to control the molecular weight distribution (MWD).…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium morphology development in seeded emulsion polymerization. IV. Influence of chain transfer agent

Stubb

Sundberg

2006

J of Applied Polymer Sci

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ABSTRACT:We performed a series of experiments to study the effect of a chain transfer agent, n-dodecyl mercaptan (n-DM), on the development of morphology in composite latex particles. The morphologies were determined using a combination of transmission electron microscopy, differential scanning calorimetry, and surfactant titration. The polymer molecular weights were reduced up to 10-fold with n-DM levels up to 1.4% in the monomer. The addition of n-DM can increase the extent to which second-stage polymer domains are formed within the interior regions of the seed particles, but this is only expected under specific conditions. Numerical simulations support this conclusion. We also observed that the reduction in the molecular weight of the second-stage polymer did not significantly increase the extent of phase separation and morphology rearrangement within the particles. The overall effect on the morphology was limited.

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Diffusional limitations in emulsion polymerization

Cited by 11 publications

References 0 publications

Diffusion‐Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

Diffusion‐Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

Emulsion polymerization of styrene with Iso‐octyl‐3‐mercaptopropionate as chain transfer agent

Nonequilibrium morphology development in seeded emulsion polymerization. IV. Influence of chain transfer agent

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