Morphology of polymers precipitated from a supercritical solvent

Lele, Ashish; Shine, Annette D.

doi:10.1002/aic.690380511

Cited by 140 publications

(77 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…or supercritical fluid, usually CO, (3)(4)(5). However, for olymer foams having closed cells of size 10 pm or P smaller and a cell density of about lo8 cells ~m-~ or higher are called microcellular foams.…”

Section: Introductionmentioning

confidence: 99%

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams

Handa

Wong

Zhang

et al. 1999

Polymer Engineering & Sci

View full text Add to dashboard Cite

The solubility of CO, in PETG, a glycol-modifled PET, was measured at different tempentures and over a broad pressure range, and diffusion coefficients were derived at the corresponding conditions. The solubility of CO, is quite high. For example, almost 15 wt% CO, can be dissolved in PETG at 35°C and 6.0 MPa. Consequently, CO, is a god blowing agent for PETG. Cellular foams in the density range of about 0.04 to 1.2 g/cm3 and cell diameters in the range of about 10 to 150 pm were produced. The foam density and the cell size were found to depend on the foaming temperature and time, with larger cells obtained at higher temperatures or when the sample was foamed for a longer time. The foam density decreased with an increase in the foaming temperature to about 90°C beyond which the density tended to increase slightly due to the cell collapse or coalescence. The density reduction also depended on the pressure at which the polymer was saturated with CO,; the higher the saturating pressure at a given temperature, the greater the density reduction.

show abstract

Section: Introductionmentioning

confidence: 99%

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams

Handa

Wong

Zhang

et al. 1999

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…The introduction of a compressed fluid anti-solvent to a solution of polycarbonate and poly(styrene-co-acrylonitrile) in liquid, rather than supercritical, CO 2 results in precipitation of a kinetically-trapped polymer blend. This same approach to frozen-in morphologies has been previously utilized [273] to alter the microphase-separation tendency of incompatible block copolymers.…”

Section: Copolymer Self-organizationmentioning

confidence: 86%

Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

2008

View full text Add to dashboard Cite

Environmentally‐responsible materials processing is becoming an important global consideration in a wide variety of technologies, especially those wherein volatile and/or residual organic solvents cannot be tolerated. In this context, polymer processing has benefited tremendously from advances achieved using high‐pressure CO2 as a viscosity modifier, plasticizing agent, foaming agent, and reaction medium. Pressurized CO2 is environmentally benign, inexpensive, sustainable, and versatile owing to its gas‐like viscosity and liquid‐like solubility, which can be tuned through judicious choice of temperature and pressure. The addition of high‐pressure CO2 to homopolymer blends and block copolymers can have a profound impact on polymer thermodynamics and kinetic processes since the number of interacting species increases. As a result, the compressibility as well as plasticization and intermolecular screening effects become non‐negligible. In this work, we review how these factors influence such polymeric systems, and discuss commercial polymer processes and applications that benefit from the use of high‐pressure CO2.

show abstract

“…Additionally, a constant value was assumed for the friction factor in the momentum equation, as has been done in many studies. 40,43,44,53,[62][63][64] In reality, however, the friction factor would depend on the flow rate, and thus, would be a function of position. Moreover, in the free expansion, the 1D flow approximation would not be applicable.…”

Section: Discussionmentioning

confidence: 98%

Deagglomeration of nanoparticle aggregates via rapid expansion of supercritical or high‐pressure suspensions

To¹,

Davé²,

Yin³

et al. 2009

AIChE Journal

View full text Add to dashboard Cite

Deagglomeration of suspensions of alumina and titania nanopowders (i.e., nanoparticle aggregates) via rapid expansion of supercritical suspensions (RESS) or high-pressure suspensions (REHPS) was studied. The size distribution of fragmented nanopowders was characterized by online Scanning Mobility Particle Spectrometer (SMPS) and Aerodynamic Particle Sizer (APS), and by offline Scanning Electron Microscopy (SEM). SMPS and SEM measurements indicate that the average agglomerate sizes were well below 1 lm, consistent with the length scales observed in our complementary RESS/REHPS mixing experiments using alumina and silica nanopowders. The APS measurements, on the other hand, were affected by reagglomeration during sampling and yielded an agglomerate size range of 1 to 3 lm. Analysis of the RESS/ REHPS process through compressible flow models revealed that both the shear stress in the nozzle and the subsequent impact of the agglomerates with the Mach disc in the free expansion region can lead to micron or sub-micron level deagglomeration. V

show abstract

Morphology of polymers precipitated from a supercritical solvent

Cited by 140 publications

References 25 publications

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams

Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

Deagglomeration of nanoparticle aggregates via rapid expansion of supercritical or high‐pressure suspensions

Contact Info

Product

Resources

About

Morphology of polymers precipitated from a supercritical solvent

Cited by 140 publications

References 25 publications

Some thermodynamic and kinetic properties of the system PETG‐CO2, and morphological characteristics of the CO2‐blown PETG foams

Some thermodynamic and kinetic properties of the system PETG‐CO2, and morphological characteristics of the CO2‐blown PETG foams

Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

Deagglomeration of nanoparticle aggregates via rapid expansion of supercritical or high‐pressure suspensions

Contact Info

Product

Resources

About

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams

Some thermodynamic and kinetic properties of the system PETG‐CO₂, and morphological characteristics of the CO₂‐blown PETG foams