High‐conversion emulsion polymerization

Maxwell, Ian; Verdurmen, Edwin M.; German, Anton L.

doi:10.1002/macp.1992.021931016

Cited by 15 publications

(5 citation statements)

References 26 publications

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“…Initially, the absorption of isoprene into the polymer particles will be restricted, as can be seen in Figure 5, by the low molecular mobility of the polymer, which is in the glassy state. [31][32][33] In domain 1, the sorption rate increases significantly and passes through a maximum in domain 2, corresponding to the sharp drop observed in the pressure increase, as discussed previously (Fig. 4).…”

Section: Sorption Ratesupporting

confidence: 64%

“…The sorption rate maximum can be explained by the decrease in T g of the seed polymer due to the plasticizing effect of the monomer, leading to a significant increase in the diffusion rate of the isoprene in the particles. [31][32][33] Furthermore, the latex particles still have a relatively low isoprene concentration, and this, in turn, will result in a large entropic driving force for the absorption of more monomer.…”

Section: Sorption Ratementioning

confidence: 99%

“…If the polymer produced has a low glass transition temperature, as in the present case, the internal particle viscosity in the end of the polymerization process will be lower SWELLING OF POLY(STYRENE-CO-METHACRYLIC ACID due to the higher molecular mobility of the soft polymer phase. [31][32][33]38 For most of the second-step polymerization process, the diffusion of the polymer molecules will not be restricted. In the experiment with the 50 : 50 ratio between the secondstage monomer and the seed, most of the second polymerization step will take place without any free monomer being present, resulting in restricted polymer (and monomer) diffusion.…”

Section: Internal Particle Viscositymentioning

confidence: 99%

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Swelling of poly(styrene-co-methacrylic acid) latex by isoprene

Karlsson¹,

Wesslén²

1998

J. Appl. Polym. Sci.

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Carboxylated polystyrene latex was used as seed and isoprene as the second-stage monomer in an inhibited, seeded emulsion polymerization recipe for studies of monomer swelling kinetics at 80°C during interval III of an emulsion polymerization. The isoprene was added to the reactor in small portions using a syringe, and changes in the reactor pressure were continuously measured. Isoprene was added until a free liquid monomer phase was formed; that was, interval II was reached, as indicated by no further pressure increase upon the addition of more monomer. When the observed pressure increment, Op i , per unit isoprene added was plotted as a function of the volume fraction of polymer in the latex particles, v p , the graph could be divided into 3 domains. The break points in the Op i curve could, in an analogous emulsion polymerization, be identified as the glass transition temperature for the polymer, the so-called gel point in interval III and the onset of interval III. In the second domain, where the v p was between the glass transition temperature, T g , for the seed polymer and the gel point, the value of Op i decreased significantly with increasing monomer concentration in the latex particles. This was due to the entropy of mixing and the monomer acting as a plasticizer in the seed polymer. The rate of sorption of monomer to the latex particles was low at high values of v p . It then increased rapidly with increasing monomer concentrations in the latex particles, [M] p , and a maximum was observed in domain 2. At lower values of v p the sorption rate decreased in domain 3 and finally became zero as the free liquid monomer phase started to form. Results from batch polymerization suggested that the rate of diffusion of adsorbed monomer and oligo radicals into the particles was retarded. A simplified form of the Vanzo equation was used to estimate the monomer partitioning. It predicted too high a value of [M] p , especially in domain 2 of the swelling process.

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Section: Sorption Ratesupporting

confidence: 64%

Section: Sorption Ratementioning

confidence: 99%

Section: Internal Particle Viscositymentioning

confidence: 99%

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Swelling of poly(styrene-co-methacrylic acid) latex by isoprene

Karlsson¹,

Wesslén²

1998

J. Appl. Polym. Sci.

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“…Therefore, propagation does not become diffusion-controlled [64], and the kinetics of post-polymerization is not influenced by the reaction temperature differently than the emulsion polymerization stage [65].…”

Section: Post-polymerizationmentioning

confidence: 99%

Removal of Monomers and VOCs from Polymers

Barandiaran¹,

Asúa²

2005

Handbook of Polymer Reaction Engineering

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“…In general, conventional emulsion polymerization achieves relatively high reaction rates. At the end of the polymerization, however, the reaction rate decreases significantly because of the limiting diffusion of the monomer in the polymer particles . This results in a significant amount of residual monomer in the product latex.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Residual Monomer in Latex Products by Enhanced Polymerization and Extraction in Supercritical Carbon Dioxide

Kemmere

Schilt

Cleven

et al. 2002

Ind. Eng. Chem. Res.

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One of the most important environmental incentives for the polymer industry is to reduce the residual monomer content in polymer products. In addition to the conventional techniques for the reduction of residual monomer, a process based on supercritical carbon dioxide (scCO 2 ) can be a viable alternative as both further polymerization and extraction of the monomer can occur. In this work, the reduction of methyl methacrylate (MMA) in a PMMA latex was chosen as a representative model system. Pulsed electron beam experiments were performed to study the effect of scCO 2 on the monomer concentration inside the polymer particles during the polymerization reaction. The partitioning behavior of MMA between water and scCO 2 was measured in a high-pressure extraction unit as a function of pressure and temperature. The obtained results show that the extraction of MMA is the predominant effect as compared to the enhancement of polymerization through plasticization.

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High‐conversion emulsion polymerization

Cited by 15 publications

References 26 publications

Swelling of poly(styrene-co-methacrylic acid) latex by isoprene

Swelling of poly(styrene-co-methacrylic acid) latex by isoprene

Removal of Monomers and VOCs from Polymers

Reduction of Residual Monomer in Latex Products by Enhanced Polymerization and Extraction in Supercritical Carbon Dioxide

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