Formation of polymer particles with supercritical fluids: A review

Yeo, Sang‐Do; Kiran, Erdoǧan

doi:10.1016/j.supflu.2004.10.006

Cited by 522 publications

(334 citation statements)

References 76 publications

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“…Polymer matrix foaming with supercritical fluids allows avoiding organic solvents and presents several advantages from a chemical, physical and toxicological points of view. Because of its easy processability, cheapness, non-toxicity and non-flammability, carbon dioxide is the most considered among supercritical fluids [15,16]. The usage of carbon dioxide as a solvent could lead to several advantages from a manufacturing, economical and safety points of view.…”

Section: Introductionmentioning

confidence: 99%

Mechanical behaviour of cyclic olefin copolymer/exfoliated graphite nanoplatelets nanocomposites foamed through supercritical carbon dioxide

Biani¹,

Dorigato²,

Bonani³

et al. 2016

Express Polym. Lett.

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Abstract.A cycloolefin copolymer matrix was melt mixed with exfoliated graphite nanoplatelets (xGnP) and the resulting nanocomposites were foamed by supercritical carbon dioxide. The density of the obtained foams decreased with the foaming pressure. Moreover, xGnP limited the cell growth during the expansion process thus reducing the cell diameter (from 1.08 to 0.22 mm with an XGnP amount of 10 wt% at 150 bar) and increasing the cell density (from 12 to 45 cells/mm 2 with a nanofiller content of 10 wt% at 150 bar). Electron microscopy observations of foams evidenced exfoliation and orientation of the nanoplatelets along the cell walls. Quasi-static compressive tests and tensile creep tests on foams clearly indicated that xGnP improved the modulus (up to a factor of 10 for a xGnP content of 10 wt%) and the creep stability.

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Section: Introductionmentioning

confidence: 99%

Mechanical behaviour of cyclic olefin copolymer/exfoliated graphite nanoplatelets nanocomposites foamed through supercritical carbon dioxide

Biani¹,

Dorigato²,

Bonani³

et al. 2016

Express Polym. Lett.

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“…4 Several techniques based on the use of supercritical fluids (SCFs) have been proposed, to obtain more control over powder PS; they have been reviewed in the literature. [5][6][7][8][9][10][11][12] The techniques try to take advantage of the hybrid gaslike and liquidlike properties of SCFs to obtain a better modulation of the PS of inhalable drugs; however, the results are in many cases inconclusive. 8 Supercritical assisted atomization (SAA), first proposed in 2002, 13 is one of the applications in which supercritical CO 2 (SC-CO 2 ) is used to improve the atomization process.…”

Section: Introductionmentioning

confidence: 99%

Production of cromolyn sodium microparticles for aerosol delivery by supercritical assisted atomization

2007

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The purpose of this study was to produce cromolyn sodium (CS) micrometric particles with controlled particle size (PS) and PS distribution (PSD) suitable for aerosol delivery, using a supercritical fluids-based process. CS was micronized using the supercritical assisted atomization (SAA) technique at different solute concentrations in water and different precipitation temperatures. Two techniques were used to measure PS and PSD of produced particles: scanning electron microscopy image analysis and laser scattering analysis. The 2 techniques were compared to provide a complete description of the powder obtained. High-performance liquid chromatography analysis was used to verify the absence of degradation of CS after micronization; differential scanning calorimetry, thermogravimetric analysis (TGA), and X-ray analysis were performed to study the effect of operative conditions on the crystalline structure and on the water content of SAA micronized particles. The CS particles obtained were spherical, with a volumetric percentage of particles with a diameter ranging between 1 and 5 μm of 50% to 66%. The precipitation temperature had no significant effect on PSD, but high drying temperatures led to product degradation. Increasing the concentration of CS in water solution produced an increase in PS of the micronized particles. TGA showed that the micronized CS had a different hydration state than the untreated CS did. The micronized product was stable after 12 months of storage, and no modifications in structure, morphology, or crystallinity were detected. In conclusion, SAA is an efficient technique for micronization of CS, and stable spherical amorphous particles suitable for aerosol delivery can be produced.

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“…Application research on Supercritical fluids become wide spread in the fields of extraction, solvent, chemical process, nano and micro particle formation, and power generation [1][2][3][4][5]. Supercritical fluids have the unique characteristics of the supercritical fluids such as high solubility, low viscosity, and high diffusivity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Supercritical Fluids as an Insulating Medium for High Speed Switching

Shon¹,

Song²,

Oh³

et al. 2016

Journal of Electrical Engineering and Technology

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-The paper investigates the insulation properties of the supercritical CO 2 (SCCO 2 ) fluid as an insulating medium for electrical apparatuses. The insulating material is crucial for electrical apparatuses and SF 6 gas has been widely used for high power electrical apparatuses. There have been many research efforts to develop substituents for SF 6 gas because of high global warming potential. We obtained above 350 kV/mm insulation strength with 12.0 MPa SCCO 2 . The positive and negative IEC standard pulses are applied between two 10 mm diameter spherical electrodes. The insulation strength of SCCO 2 is at least 2.5 times higher than that of CO 2 gas at 6.0MPa. The insulation strength of SCCO 2 fluid is about 10 times higher than that of SF 6 at 0.5MPa which is the ordinary operating pressure of electrical switchgears. Using the result, we expect that the time for switching and dielectric recovery could be reduced using SCCO 2 fluid as an insulating medium.

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Formation of polymer particles with supercritical fluids: A review

Cited by 522 publications

References 76 publications

Mechanical behaviour of cyclic olefin copolymer/exfoliated graphite nanoplatelets nanocomposites foamed through supercritical carbon dioxide

Mechanical behaviour of cyclic olefin copolymer/exfoliated graphite nanoplatelets nanocomposites foamed through supercritical carbon dioxide

Production of cromolyn sodium microparticles for aerosol delivery by supercritical assisted atomization

Investigation of the Supercritical Fluids as an Insulating Medium for High Speed Switching

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