Solid‐state microcellular and nanocellular polysulfone foams

Guo, Huimin; Nicolae, Andrei; Kumar, Vipin

doi:10.1002/polb.23719

Cited by 55 publications

(61 citation statements)

References 46 publications

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“…This critical CO 2 mass uptake has been reported in different studies and for different systems. A similar result was observed for PSU by Guo et al [7] they found a critical gas uptake between 10% and 12%. For materials like PEI, the critical concentration is similar to the PPSU one, between 9.4% and 11% [12] while there are polymers that need higher gas concentrations in order to lead nanocells.…”

Section: Influence Of the Saturation Pressuresupporting

confidence: 88%

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Production and characterization of nanocellular polyphenylsulfone foams

2016

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a b s t r a c t Nanocellular foams have been produced by means of a gas dissolution process using polyphenylsulfone (PPSU) as matrix polymer. Cell sizes in the range 20-30 nm and cell nucleation densities higher than 10 15 cm À 3 have been achieved for materials with relative densities in the range 0.65-0.75. The influence of both saturation pressure and foaming temperature has been studied. On the one hand, it has been proved that there is a large influence of the amount of gas (CO 2 ) absorbed in the final cellular structure, in fact it has been found a critical CO 2 uptake between 9% and 9.5% at which the cell sizes evolve from the micro to the nanoscale. On the other hand, it has been found that there is a wide range of foaming parameters (foaming time and foaming temperature) in which nanocellular foams can be produced.

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Section: Influence Of the Saturation Pressuresupporting

confidence: 88%

“…For polycarbonate (PC) systems, Guo et al [6] obtained cell sizes of the order of 20 nm and relative densities around 0.6 working with low saturation temperatures. Engineering polymers such as polysulfone (PSU) have been tested as well, producing nanocellular foams with cell sizes ranging 20-80 nm and relative densities of 0.6-0.8 [7].…”

Section: Introductionmentioning

confidence: 99%

Production and characterization of nanocellular polyphenylsulfone foams

2016

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“…PC or PC/GnP composites that were not soaked with scCO 2 did not show any appreciable crystallinity. It is well know the plasticizing effect of CO 2 in polymers, increasing chain mobility which has been observed to decrease the glass transition temperature [32][33][34][35] and increase ordered structures in polymers [31]. Table 1.…”

Section: Cellular and Composite Morphologymentioning

confidence: 99%

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

et al. 2016

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Abstract:The dielectric and electromagnetic interference (EMI) shielding properties of polycarbonate/graphene nanocomposites foamed using supercritical carbon dioxide were studied as a function of their cellular and composite morphology. Foamed polycarbonate filled with 0.5% (by weight) graphene exhibited enhanced EMI shielding effectiveness, which was found to depend on cellular and composite morphology in a complex manner.Foamed composites presented a maximum specific EMI shielding effectiveness of ~39 dB.cm 3 /g, which is approximately 35 times greater than that of unfoamed composite (1.1 dB.cm 3 /g). In addition, the relative permittivity was found to increase up to 3.25 times. The results suggest that graphene filled polymer foams can enhance the performance of electronic devices, opening up the possibility of using these materials in electronic applications.

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“…where n, M, and A are the number of cells in the micrograph, magnification of the micrograph, and area of the micrograph (cm 2 ), respectively [35]. The foaming rate of the foamed PP, R a , was the ratio of the sum of the areas of bubble holes to the total area, and was calculated as follows:…”

Section: Morphology Of Foammentioning

confidence: 99%

Supercritical CO2 Foaming of Radiation Cross-Linked Isotactic Polypropylene in the Presence of TAIC

et al. 2016

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Abstract:Since the maximum foaming temperature window is only about 4 • C for supercritical CO 2 (scCO 2 ) foaming of pristine polypropylene, it is important to raise the melt strength of polypropylene in order to more easily achieve scCO 2 foaming. In this work, radiation cross-linked isotactic polypropylene, assisted by the addition of a polyfunctional monomer (triallylisocyanurate, TAIC), was employed in the scCO 2 foaming process in order to understand the benefits of radiation cross-linking. Due to significantly enhanced melt strength and the decreased degree of crystallinity caused by cross-linking, the scCO 2 foaming behavior of polypropylene was dramatically changed. The cell size distribution, cell diameter, cell density, volume expansion ratio, and foaming rate of radiation-cross-linked polypropylene under different foaming conditions were analyzed and compared. It was found that radiation cross-linking favors the foamability and formation of well-defined cell structures. The optimal absorbed dose with the addition of 2 wt % TAIC was 30 kGy. Additionally, the foaming temperature window was expanded to about 8 • C, making the handling of scCO 2 foaming of isotactic polypropylene much easier.

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Solid‐state microcellular and nanocellular polysulfone foams

Cited by 55 publications

References 46 publications

Production and characterization of nanocellular polyphenylsulfone foams

Production and characterization of nanocellular polyphenylsulfone foams

Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

Supercritical CO2 Foaming of Radiation Cross-Linked Isotactic Polypropylene in the Presence of TAIC

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