Extruded Open-Cell Foams Using Two Semicrystalline Polymers with Different Crystallization Temperatures

Lee, Patrick; Wang, Jin; Park, Chul

doi:10.1021/ie050498j

Cited by 157 publications

(82 citation statements)

References 10 publications

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“…Similarly, there are some reports about clay reinforced nanocomposite foams based on semicrystalline polymers [5][6][7][8]. Moreover, microcellular foaming process is one of the techniques that have been studied for this purpose [9][10][11][12][13][14][15][16]. By rapid pressure quenching [17], melt blending using polymers with high glass tran-sition temperature (T g ) [4] and incorporating nanoclay into polymers [7], micron or submicron size cellular structures have been successfully obtained.…”

Section: Introductionmentioning

confidence: 99%

Assisted heterogeneous multinucleation and bubble growth in semicrystalline ethylene-vinyl acetate copolymer/expanded graphite nanocomposite foams: Control of morphology and viscoelastic properties

Yousefzade¹,

Hemmati²,

Garmabi³

et al. 2015

Express Polym. Lett.

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Abstract. Nanocomposite foams of ethylene-vinyl acetate copolymer (EVA) reinforced by expanded graphite (EG) were prepared using supercritical nitrogen in batch foaming process. Effects of EG particle size, crosslinking of EVA chains and foaming temperature on the cell morphology and foam viscoelastic properties were investigated. EG sheet surface interestingly provide multiple heterogeneous nucleation sites for bubbles. This role is considerably intensified by incorporating lower loadings of EG with higher aspect ratio. The amorphous and non-crosslinked domains of EVA matrix constitute denser bubble areas. Higher void fraction and more uniform cell structure is achieved for non-crosslinked EVA/EG nanocomposites foamed at higher temperatures. With regard to the structural variation, the void fraction of foam samples decreases with increasing the EG content. Storage and loss moduli were analyzed to study the viscoelastic properties of nanocomposite foams. Surprisingly, the foaming process of EVA results in a drastic reduction in loss and storage moduli regardless of whether the thermoplastic matrix contains EG nanofiller or not. For the EVA/EG foams with the same composition, the nanocomposite having higher void fraction shows relatively lower loss modulus and more restricted molecular movements. The study findings have verified that the dynamics of polymer chains varies after foaming EVA matrix in the presence of EG.

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Section: Introductionmentioning

confidence: 99%

Assisted heterogeneous multinucleation and bubble growth in semicrystalline ethylene-vinyl acetate copolymer/expanded graphite nanocomposite foams: Control of morphology and viscoelastic properties

Yousefzade¹,

Hemmati²,

Garmabi³

et al. 2015

Express Polym. Lett.

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show abstract

“…Current from the anode to cathode, shown in figure [2] and by equations [1] and [2], is reduced by the resistance of the current carrier, due to structural interference, shown in figure [5] 21 . Graphene can overcome this problem in the form of carbon nanotubes (CNTs).…”

Section: Resultsmentioning

confidence: 99%

“…Other "newer" polymer membranes do not have this drawback, such as using a Phosphoric Acid based membrane. These membranes can operate at temperatures of 220 o C, these types of membranes are not common due to acid leeching through the system and the difficulty of mixing and creating the polymers 5 .…”

Section: Nano Filters/membranesmentioning

confidence: 99%

“…For homogeneous systems, enthalpy is solely based on the size of the system as it is an extensive property 10 . This is shown in equation [5], where enthalpy (H) is the sum of the internal energy of the system (U) and the product of pressure (P) and volume (V) of the system 9 . The change in enthalpy in a system is equal to the heat gained or lost in the system 11 .…”

Section: Thermodynamicsmentioning

confidence: 99%

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Thermodynamic Effects of Nanotechnological Augmentation of Hydrogen Fuel Cells

Woodley

Yang

Tanner

et al. 2017

PAMR

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This meta-study focuses on the research regarding the use of nanotechnology in traditional fuel cells in order to increase thermodynamic efficiency through the exploitation of various thermodynamic systems and theories. The use of nanofilters and nano-structured catalysts improve the fuel cell system through the means of filtering molecules from protons and electrons significantly increases the possible output of the fuel cell and the use of nano-platinum catalysts to lower the activation energy of the fuel cell chemical reaction a notable amount resulting in a more efficient system and smaller entropy in comparison to the use of macro sized catalysts.

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“…Different factors such as non-homogeneity of the foam material affect porosity and reticulation rate of foams. 17,18 In the present paper, reticulation rate R w will be used as a microstructural parameter to apply the effect of processing parameters into the proposed model. Cell length and cell wall thickness can be estimated from SEM images and porosity measurements.…”

mentioning

confidence: 99%

A semi-empirical model relating micro structure to acoustic properties of bimodal porous material

Mosanenzadeh

Doutres

Naguib

et al. 2015

Journal of Applied Physics

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Complex morphology of open cell porous media makes it difficult to link microstructural parameters and acoustic behavior of these materials. While morphology determines the overall sound absorption and noise damping effectiveness of a porous structure, little is known on the influence of microstructural configuration on the macroscopic properties. In the present research, a novel bimodal porous structure was designed and developed solely for modeling purposes. For the developed porous structure, it is possible to have direct control on morphological parameters and avoid complications raised by intricate pore geometries. A semi-empirical model is developed to relate microstructural parameters to macroscopic characteristics of porous material using precise characterization results based on the designed bimodal porous structures. This model specifically links macroscopic parameters including static airflow resistivity ðrÞ, thermal characteristic length ðK 0 Þ, viscous characteristic length ðKÞ, and dynamic tortuosity ða 1 Þ to microstructural factors such as cell wall thickness ð2tÞ and reticulation rate ðR w Þ. The developed model makes it possible to design the morphology of porous media to achieve optimum sound absorption performance based on the application in hand. This study makes the base for understanding the role of microstructural geometry and morphological factors on the overall macroscopic parameters of porous materials specifically for acoustic capabilities. The next step is to include other microstructural parameters as well to generalize the developed model. In the present paper, pore size was kept constant for eight categories of bimodal foams to study the effect of secondary porous structure on macroscopic properties and overall acoustic behavior of porous media. V C 2015 AIP Publishing LLC.

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Extruded Open-Cell Foams Using Two Semicrystalline Polymers with Different Crystallization Temperatures

Cited by 157 publications

References 10 publications

Assisted heterogeneous multinucleation and bubble growth in semicrystalline ethylene-vinyl acetate copolymer/expanded graphite nanocomposite foams: Control of morphology and viscoelastic properties

Assisted heterogeneous multinucleation and bubble growth in semicrystalline ethylene-vinyl acetate copolymer/expanded graphite nanocomposite foams: Control of morphology and viscoelastic properties

Thermodynamic Effects of Nanotechnological Augmentation of Hydrogen Fuel Cells

A semi-empirical model relating micro structure to acoustic properties of bimodal porous material

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