Initial droplet size distribution in miniemulsion polymerization

Sood, Ashwini; Awasthi, Seema

doi:10.1002/app.11873

Cited by 27 publications

(38 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We considered this phenomena in explaining the instability seen in the miniemulsion system. [14] This analysis led to the conclusions that the initial droplet distribution should contain a significant fraction of small sized particles, which is true for a broad distribution. Further, this distribution will be bimodal when unstable.…”

Section: Stability Of the Droplet Size Distributionmentioning

confidence: 98%

“…In recent works, the stability of the miniemulsion droplet size distribution and the nature of the initial droplet size distribution were discussed. [13,14] It was concluded that the initial droplet size distribution in miniemulsion polymerization is broad and can be bimodal. The resulting particle size distribution is also very broad and also reported to be bimodal.…”

Section: Basic Features Of Miniemulsion Polymerization Processmentioning

confidence: 99%

“…This distribution is determined by pre-emulsification and emulsification steps. [14] Variations in the emulsification steps (viz. the type and amount of co-stabilizer, the intensity and uniformity of the energy input, etc.)…”

Section: Initial Droplet Size Distributionmentioning

confidence: 99%

“…[10,24] A theoretical analysis to reconcile the afore-mentioned experimental observations in terms of a suitable theoretical framework was conducted. [13,14] The instability may arise as a result of coalescence which results from an insufficient barrier (electrostatic, viscoelastic, etc.) against contact or from molecular diffusion (popularly known as Ostwald ripening).…”

Section: Stability Of the Droplet Size Distributionmentioning

confidence: 99%

See 3 more Smart Citations

Population Balance Model for Miniemulsion Polymerization, 1

Sood

Awasthi

2004

Macro Theory & Simulations

View full text Add to dashboard Cite

Summary: Miniemulsion polymerization is a relatively new process that can produce polymer latexes of unusual characteristics. The initial droplet size distribution and the final particle size distribution in miniemulsion polymerization are broad. This has not been addressed by the present models that assume monodisperse droplet size and particle size distributions. A population balance framework for the miniemulsion polymerization that incorporates both the droplet size distribution and the particle size distribution is developed in this work.

show abstract

Section: Stability Of the Droplet Size Distributionmentioning

confidence: 98%

Section: Basic Features Of Miniemulsion Polymerization Processmentioning

confidence: 99%

Section: Initial Droplet Size Distributionmentioning

confidence: 99%

Section: Stability Of the Droplet Size Distributionmentioning

confidence: 99%

See 2 more Smart Citations

Population Balance Model for Miniemulsion Polymerization, 1

Sood

Awasthi

2004

Macro Theory & Simulations

View full text Add to dashboard Cite

show abstract

“…The distribution of most interest for release experiments is that of the volume, as the release profile is mainly determined by the microcapsules that contain most of the oil in volume/ weight. The capsule size is commonly correlated using a lognormal distribution (Poncelet De Smet et al, 1989;Hollingsworth and Johns, 2003;Sood and Awasthi, 2003), Figure 2 shows a typical size distribution for MF microcapsules. From such data, the lognormal mean size (d LN ) and the lognormal standard deviation ( LN ) (see Figure 3 inset) are calculated, where d, defined as the decimal antilogarithm of d LN , is equal to D 4,3 , the volume moment mean diameter, if there is only a single size distribution.…”

Section: Effect Of the Size Polydispersitymentioning

confidence: 99%

Determination of the shell permeability of microcapsules with a core of oil-based active ingredient

Mercadé‐Prieto

Allen

York

et al. 2012

Journal of Microencapsulation

View full text Add to dashboard Cite

An experimental and theoretical methodology is proposed to calculate the permeability of microcapsules that contain a core of oil-based active ingredient. Theoretical analysis is performed considering the polydispersity of the measurable capsule size, which allows the estimation of the permeability polydispersity via three different methods. The models proposed were applied in order to determine the permeability of melamine-formaldehyde microcapsules with hexyl salicylate as core oil. Release experiments were performed with four different co-solvents (ethanol, propan-1-ol, propan-2-ol and 1,3-butanediol) of different concentration. Permeability values were found to be constant, despite a two order magnitude of difference in the solubility concentrations.

show abstract

Particle size distribution control in emulsion polymerization

Sood

2004

J of Applied Polymer Sci

View full text Add to dashboard Cite

Effects of the operating policies-the initial initiator amount; the initial emulsifier amount; the monomer addition mode: batch or semibatch; and the monomer addition rate under "monomer-starved conditions" for the control of particle size distribution (PSD)-were studied through a model that simulates batch and semibatch reactor operations in conventional emulsion polymerization. The population balance model incorporates both the nucleation stage and the growth stage. The full PSDs were reported, which have normally been omitted in earlier studies. It was shown through simulations that the broadness of the distributions, both initial (obtained after the end of nucleation) and final (after complete conversion of monomer), can be controlled by the initial initiator amount and the emulsifier amount. The higher initiator amounts and the lower emulsifier amounts favor narrower initial and final distributions. The shape of the initial PSDs and the trends in the average size and range were preserved with subsequent addition of monomer in the batch or in the semibatch mode, although the final PSD was always considerably narrower than that of the initial PSD. The addition of monomer in the semibatch mode gave narrower distribution compared to that of the batch mode, and also, lower monomer addition rates gave narrower distributions (larger average sizes), which was a new result. It was further shown through simulations that, under monomer-starved conditions, the reaction rate closely matched the monomer feed rate. These conclusions are explained (1) qualitatively-the shorter the length of the nucleation stage and the larger the length of the growth stage (provided the number of particles remains the same), the narrower is the distribution; and (2) mathematically-in terms of the "self-sharpening" effect. Experimental evidence in favor of the self-sharpening effect was given by analyzing the experimental particle size distributions in detail. The practical significance of this work was proposed.

show abstract

Initial droplet size distribution in miniemulsion polymerization

Cited by 27 publications

References 7 publications

Population Balance Model for Miniemulsion Polymerization, 1

Population Balance Model for Miniemulsion Polymerization, 1

Determination of the shell permeability of microcapsules with a core of oil-based active ingredient

Particle size distribution control in emulsion polymerization

Contact Info

Product

Resources

About