• Elastomers and Composites
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• v.44 no.3
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• pp.222-231
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• 2009

Shirasu-porous-glass (SPG) membrane emulsification is highly attractive in the field of toner industries, foods and drug delivery systems because of its easy control of particle size in micro-scale, narrow size distribution and multiple emulsion. The particle size and morphology of emulsion droplets can be controlled by changing the type of initiators, additives, monomers, crosslinkers and inhibitors in SPG membrane emulsification. In this paper, principles of SPG membrane emulsification, influence of process parameters and industrial applications have been addressed.

• Membrane Journal
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• v.31 no.1
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• pp.52-60
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• 2021

When preparing calcium alginate microspheres using rotating membrane emulsification that rotates SPG (Shirasu porous glass) tubular membrane in the continuous phase, the optimal conditions of rotating membrane emulsification process parameters for producing monodisperse microspheres were determined. We determined the effects of process parameters of rotating membrane emulsification (the rotating speed of membrane module, the transmembrane pressure, the ratio of dispersed phase to continuous phase, the alginate concentration, the emulsifier concentration, the stabilizer concentration, the crosslinking agent concentration, and the membrane pore size) on the mean size and size distribution of alginate microspheres. As a result, the size of the microspheres decreased as the rotating speed of membrane module, the emulsifier concentration, and the crosslinking agent concentration increased among the process parameters of rotating membrane emulsification. On the contrary, as the ratio of dispersed phase to continuous phase, the transmembrane pressure, and the alginate concentration increased, the size of the microspheres increased. In the rotating membrane emulsification using an SPG membrane with a pore size of 3.2 ㎛, it was possible to finally prepare monodisperse alginate microspheres with a particle size of 4.5 ㎛ through the control of process parameters.

• Membrane Journal
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• v.14 no.3
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• pp.218-229
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• 2004

We prepared monodispersed calcium alginate microspheres by controlling various conditions of emulsification procedure using a lab-scale batch type membrane emulsification system equipped with SPG (Shirasu porous glass) tubular membranes. We determined the effects of process parameters of membrane emulsification (ratio of dispersed phase to continuous phase, alginate concentration, emulsifier concentration, type and concentration of stabilizer, transmembrane pressure, concentration of crosslinking agent, stirring speed and membrane pore size) on the mean size and size distribution of alginate microspheres. The increase of the ratio of dispersed phase to continuous phase, transmembrane pressure and alginate concentration led to the increase in the mean size of alginate microspheres. On the contrary, the increase in emulsifier concentration, stirring speed of the continuous phase and concentration of the crosslinking agent caused the reduction of the mean size of microspheres. Through controlling these parameters, monodisperse alginate microspheres with about $6{\mu}{\textrm{m}}$ of the mean size and 1.1 of the size distribution value were finally prepared in case of the using SPC membrane with the pore size of $2.9{\mu}{\textrm{m}}$.

• Membrane Journal
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• v.27 no.6
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• pp.511-518
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• 2017

The membrane emulsification (ME) is a technology for producing emulsions with narrow size distribution by using the well-defined porous membranes such as the SPG membrane. In this study, the preparation of polycaprolactone (PCL) microcapsules by using the multiple emulsions obtained from membrane emulsification method is studied. After the making of $W_1/O$ single emulsions by sonication method, then $W_1/O/W_2$ multiple emulsions are formed by premix-ME method. The PCL microcapsules impregnated with BSA model drug are prepared by solvent evaporating from $W_1/O/W_2$ multiple emulsions. The effects of various parameters such as the ratio of disperse/continuous phase (D/C ratio), the concentration of PCL, emulsifier and model drug and the transmembrane pressure on the size and distribution of PCL microcapsules are investigated. The uniform PCL microcapsules with about $5{\sim}6{\mu}m$ of mean size and 26% of BSA loading are obtained by the premix membrane emulsification.

• Membrane Journal
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• v.17 no.1
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• pp.67-79
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• 2007

Uniform microcapsules containing ionic model drugs were prepared by controlling various conditions of emulsification procedure using a lab-scale membrane emulsification system with a SPG (Shirasu porous glass) tubular membrane. We observed the effects of various emulsification parameters [concentration and molecular weight of polycaprolatone (PCL) polymer, transmembrane pressure and emulsifier concentration in disperse phase and continuous phase, stirring speed] on the mean size and size ditribution of microcapsules containing lidocaine hydrochloride (cationic drug), sodium salicylate (nonionic drug) and 4-acetaminophen (anionic drug) used as a model drugs. Also, release characteristics of a model drugs from PCL microcapsules were investigated. Controlling membrane emulsification parameters, uniform PCL microcapsules with about $5\;{\mu}m$ of the mean size were finally prepared. The release rate and the burst effect of microcapsules were decreased in condition of the acidic solution, but it was increased in condition of the base solution.

• Membrane Journal
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• v.19 no.2
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• pp.122-128
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• 2009

We prepared monodispersed spherical silica microgels by controlling various conditions of emulsification procedure using a lab-scale membrane emulsification system equipped with SPG (Shirasu porous glass) porous membrane having pore size of $1.5{\mu}m$. We determined the effects of process parameters of membrane emulsification (ratio of dispersed phase to continuous phase, sodium silicate concentration, emulsifier concentration, dispersed phase pressure, stirring speed) on the mean size and size distribution of silica microgels. The increase of the ratio of dispersed phase to continuous phase, dispersed phase pressure and sodium silicate concentration led to the increase in the mean size of microgels. On the contrary, the increase in emulsifier concentration and stirring speed of the continuous phase caused the reduction of the mean size of microgels. Through controlling these parameters, monodisperse spherical silica microgels with about $6{\mu}m$ of the mean size were finally prepared.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2058-2071
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• 2015

A comparative study was conducted to evaluate precision and accuracy in controlling the temperature dependence of encapsulated microbial time-temperature integrators (TTIs) developed using two different emulsification techniques. Weissela cibaria CIFP 009 cells, immobilized within 2% Na-alginate gel microbeads using homogenization (5,000, 7,000, and 10,000 rpm) and Shirasu porous glass (SPG) membrane technologies (10 μm), were applied to microbial TTIs. The prepared micobeads were characterized with respect to their size, size distribution, shape and morphology, entrapment efficiency, and bead production yield. Additionally, fermentation process parameters including growth rate were investigated. The TTI responses (changes in pH and titratable acidity (TA)) were evaluated as a function of temperature (20℃, 25℃, and 30℃). In comparison with conventional methods, SPG membrane technology was able not only to produce highly uniform, small-sized beads with the narrowest size distribution, but also the bead production yield was found to be nearly 3.0 to 4.5 times higher. However, among the TTIs produced using the homogenization technique, poor linearity (R²) in terms of TA was observed for the 5,000 and 7,000 rpm treatments. Consequently, microbeads produced by the SPG membrane and by homogenization at 10,000 rpm were selected for adjusting the temperature dependence. The E_a values of TTIs containing 0.5, 1.0, and 1.5 g microbeads, prepared by SPG membrane and conventional methods, were estimated to be 86.0, 83.5, and 76.6 kJ/mol, and 85.5, 73.5, and 62.2 kJ/mol, respectively. Therefore, microbial TTIs developed using SPG membrane technology are much more efficient in controlling temperature dependence.

• Membrane Journal
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• v.20 no.2
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• pp.87-96
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• 2010

We prepared spherical silica particles by controlling various conditions of emulsion-gel procedure using a lab-scale membrane emulsification system equipped with SPG (Shirasu porous glass) membrane having pore size of 2.6 ${\mu}m$. We determined the effects of process parameters of membrane emulsification (dispersed phase pressure, stabilizer and emulsifier concentration in continuous phase, $H_2O$/TEOS ratio, ratio of dispersed phase to continuous phase) on the mean size and size distribution of silica particles. The increase of the dispersed phase pressure and ratio of dispersed phase to continuous phase led to the increase in the mean size of silica particles. On the contrary, the increase in stabilizer and emulsifier concentration and $H_2O$/TEOS ratio caused the reduction of the mean size of particles. Through controlling these parameters, monodisperse spherical silica particles with about 3 ${\mu}m$ of the mean size were finally prepared.

• Journal of Adhesion and Interface
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• v.16 no.2
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• pp.76-82
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• 2015

W/O emulsions were prepared from the aqueous solution containing NIPAAm, MBA, and APS in the continuous phase of toluene and mineral oil mixture with HMP and Span80 by using SPG membrane emulsification, and followed by the formation of PNIPAAm hydrogel microspheres through UV photopolymerization. As the ratio of mineral oil to toluene increased in the continuous phase, both particle size of the hydrogel increased and density of PNIPAAm polymer in the hydrogel particle increased, and which significantly affected swelling/deswelling ratio ($V/V_o$) with temperature change around VPTT. When the polymerization temperature was below LCST ($20^{\circ}C$), PNIPAAm hydrogel showed filled particle morphology; however, it was turned out to hollow particle morphology with thick shell layer with $40^{\circ}C$. Both density of PNIPAAm and gel content of the hydrogel increased with the increase in MBA concentration.

• Polymer(Korea)
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• v.39 no.1
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• pp.78-87
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• 2015

With aiming to prepare microcapsules having a particle size of $30-50{\mu}m$, thermally expandable capsules with relatively uniform particle sizes consisting of a n-octane/poly(acrylonitrile-co-methyl methacrylate) core/shell structure were synthesized using SPG membrane emulsification and suspension polymerization. Four steric stabilizers and five crosslinking agents were employed. When poly(vinyl alcohol) as a stabilizer was used, the prepared capsules showed a smooth and regular morphology and the liquid hydrocarbon (n-octane) was well encapsulated in the core. When 1,4-butnaediol methacrylate (BDDMA) was used as a crosslinker, the uniform capsules with the average diameter of $36.8{\mu}m$ were synthesized. The capsules prepared with 0.05 mol% BDDMA showed the best encapsulation efficiency.