Processing of microcellular nanocomposite foams by using a supercritical fluid

Wee, Dongho; Seong, Dong Gi; Youn, Jae Ryoun

doi:10.1007/bf02902932

Cited by 22 publications

(5 citation statements)

References 26 publications

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“…Although at surfaces provide the lowest energy barrier to nucleation, the presence of nano-sized llers still decreases the energy-barrier for cell nucleation compared to that required for homogeneous nucleation and forces the nucleation to occur at the ller-polymer interface. [37][38][39] The large number of nanollers provides many more nucleation sites, leading to a smaller average cell size. Therefore, the addition of inorganic particles (llers) induces heterogeneous nucleation, provides a large number of nucleation sites, and provides a small average cell size and narrow cell size distribution.…”

Section: Thermodynamics Of Nucleationmentioning

confidence: 99%

“…5 A summary of literature data showing the increase in cell number density and decrease in cell size of PMMA foams due to the addition of nanofillers. 18,20,27,36,[40][41][42][43][44][45][46][47] leads to lowered cell density at low temperatures. At high temperatures (above the glass transition temperature), although bubble growth is easier due to low polymer viscosity, growing bubbles can easily coalesce, leading to decreased cell density.…”

Section: Thermodynamics Of Nucleationmentioning

confidence: 99%

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Polymer nanocomposite foams

et al. 2013

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Polymer nanocomposite foams, polymer foams with nanoparticles, are an intriguing class of materials with unique structure and properties. The shape, size and surface chemistry of nanoparticles can be tailored to control the foam structure, and therefore, foam properties. Nanoparticles also add functionality to polymer foams. In this paper, we briefly review the recent developments in polymer nanocomposites and nanocomposite foams. This is followed by an extensive discussion regarding the role of nanoparticles in foam morphology and properties. Finally, the current and future trends of polymer nanocomposite foams are summarized. Both challenges and opportunities in this field are discussed. LimengChen received a B.S. degree in Materials Science and Engineering from Zhejiang University in Hangzhou, China and a Ph.D. degree in Materials Engineering from Rensselaer Polytechnic Institute. He is currently a R&D Engineer at Cabot Corporation. Deniz Rende is currently working as a post-doctoral researcher at Rensselaer Polytechnic Institute, USA. She received her Ph.D. degree from the Department of Chemical Engineering at Bogazici University, Turkey. Her current research focuses on supercritical uid assisted processing of polymer nanocomposites and foams.

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Section: Thermodynamics Of Nucleationmentioning

confidence: 99%

Section: Thermodynamics Of Nucleationmentioning

confidence: 99%

Polymer nanocomposite foams

et al. 2013

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“…Cell size, size distribution and cell density depend on the cell nucleation and cell growth mechanisms, all of which contribute to the final bulk density of the product. The cell size is inversely proportional to the number of nucleation sites, and the percentage of nanofillers can increase the nucleation rate [14][15][16][17][18][19][20][21][22][23][24][25][26] ; for this reason, in this work, we have used the percentage of filler up to 10%. An improvement of thermal and mechanical properties has been reached, and these results have been compared with morphological analyses performed with scanning electron microscopy (SEM).…”

Section: Introductionmentioning

confidence: 99%

Thermal and mechanical performance of rigid polyurethane foam added with commercial nanoparticles

Lorusso

Vergaro

Conciauro

et al. 2017

Nanomaterials and Nanotechnology

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This study investigates the effects of commercial nanoparticles on thermal and mechanical performance of rigid polyurethane foams. Two different types of nanoparticles are considered as fillers, spherical titania and rod-shaped halloysite clay nanotubes. The aim of this study was to produce rigid polyurethane foams modified with titania nanocrystals and nanohalloysite in order to obtain polyurethanes with improved properties. The laboratory scale-up will be suitable for the production in many branches of industry, such as construction and automotive production. In particular, these foams, added with commercial nanoparticles, characterized by better thermal and mechanical properties, are mainly used in construction for thermal insulation of buildings. The fillers were dispersed in the components, bringing rates up to 10%. In these investigations, the improvement of the thermal properties occurs by adding nanoparticles in the range 4-8% of titania and halloysite. The mechanical properties instead have been observed an improvement starting from 6% of nanoparticles addition. All data are in agreement with scanning electron microscope observations that shown a decrease in the average cell size and an increase in the cell density by adding nanoparticles in foams.

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“…The addition of inorganic nanoparticles, which act as nucleating agents, induces heterogeneous nucleation and provides a large number of nucleation sites. Furthermore, the presence of micro-or nanosized fillers dramatically decreases the energy barrier for cell nucleation compared to that required for homogeneous nucleation [9,13,16,17]. Existing models based on classical nucleation theories sometimes fail to explain the nucleation satisfactorily.…”

Section: Introductionmentioning

confidence: 99%

Controlling Foam Morphology of Poly(methyl methacrylate) via Surface Chemistry and Concentration of Silica Nanoparticles and Supercritical Carbon Dioxide Process Parameters

Rende

Schadler

Ozisik

2013

Journal of Chemistry

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Polymer nanocomposite foams have received considerable attention because of their potential use in advanced applications such as bone scaffolds, food packaging, and transportation materials due to their low density and enhanced mechanical, thermal, and electrical properties compared to traditional polymer foams. In this study, silica nanofillers were used as nucleating agents and supercritical carbon dioxide as the foaming agent. The use of nanofillers provides an interface upon which CO2nucleates and leads to remarkably low average cell sizes while improving cell density (number of cells per unit volume). In this study, the effect of concentration, the extent of surface modification of silica nanofillers with CO2-philic chemical groups, and supercritical carbon dioxide process conditions on the foam morphology of poly(methyl methacrylate), PMMA, were systematically investigated to shed light on the relative importance of material and process parameters. The silica nanoparticles were chemically modified with tridecafluoro-1,1,2,2-tetrahydrooctyl triethoxysilane leading to three different surface chemistries. The silica concentration was varied from 0.85 to 3.2% (by weight). The supercritical CO2foaming was performed at four different temperatures (40, 65, 75, and 85°C) and between 8.97 and 17.93 MPa. By altering the surface chemistry of the silica nanofiller and manipulating the process conditions, the average cell diameter was decreased from9.62±5.22to1.06±0.32 μm, whereas, the cell density was increased from7.5±0.5×108to4.8±0.3×1011cells/cm3. Our findings indicate that surface modification of silica nanoparticles with CO2-philic surfactants has the strongest effect on foam morphology.

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Processing of microcellular nanocomposite foams by using a supercritical fluid

Cited by 22 publications

References 26 publications

Polymer nanocomposite foams

Polymer nanocomposite foams

Thermal and mechanical performance of rigid polyurethane foam added with commercial nanoparticles

Controlling Foam Morphology of Poly(methyl methacrylate) via Surface Chemistry and Concentration of Silica Nanoparticles and Supercritical Carbon Dioxide Process Parameters

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