Micro and nano cellular amorphous polymers (PMMA, PS) in supercritical CO2 assisted by nanostructured CO2-philic block copolymers – One step foaming process

Ruiz, José A. Reglero; Pedros, Matthieu; Tallon, Jean-Marc; Dumon, Michel

doi:10.1016/j.supflu.2011.04.022

Cited by 84 publications

(67 citation statements)

References 40 publications

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“…We note that the location of this discontinuity for the PMMA-CO 2 system is within the range of experimental pressures for polymer foaming. 30 Therefore, the phenomenon predicted here should be readily observable.…”

Section: Nucleation Below T Cmentioning

confidence: 72%

Bubble nucleation in polymer–CO2 mixtures

Cristancho

Costeux

et al. 2013

Soft Matter

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We combine density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in two polymer-CO 2 mixture systems, poly(methyl methacrylate) (PMMA)-CO 2 and polystyrene (PS)-CO 2 . Nucleation is initiated by saturating the polymer liquid with high pressure CO 2 and subsequently reducing the pressure to ambient condition. Below a critical temperature (T c ), we find that there is a discontinuous drop in the nucleation barrier as a function of increased initial CO 2 pressure (P 0 ), as a result of an underlying metastable transition from a CO 2 -rich-vapor phase to a CO 2 -rich-liquid phase. The nucleation barrier is generally higher for PS-CO 2 than for PMMA-CO 2 under the same temperature and pressure conditions, and both higher temperature and higher initial pressure are required to lower the nucleation barrier for PS-CO 2 to experimentally relevant ranges. Classical nucleation theory completely fails to capture the structural features of the bubble nucleus and severely underestimates the nucleation barrier.

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Section: Nucleation Below T Cmentioning

confidence: 72%

Bubble nucleation in polymer–CO2 mixtures

Cristancho

Costeux

et al. 2013

Soft Matter

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“…27 Ruiz prepared porous polymethyl methacrylate/polystyrene (PMMA/PS) composites in the presence of BCPs, and achieved a pore size of 0.2 lm. 28 Liu found that the addition of PP can improve the pore density and reduce the pore size of polyetherimide foams. 29 Nevertheless, in the previous studies, significant amounts of additives or chemical solvents were needed, some of which were toxic.…”

Section: Introductionmentioning

confidence: 99%

Investigation of poly(l-lactic acid)/graphene oxide composites crystallization and nanopore foaming behaviors via supercritical carbon dioxide low temperature foaming

et al. 2016

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Poly(lactic acid) (PLA)/graphene oxide (GO) nanocomposites were prepared by solution mixing. Differential scanning calorimetry results indicated that GO was an effective nucleating agent. The size of spherulites decreased, the density of spherulites increased with increasing GO and the crystallinity of PLA increased from 4.34 to 49.01%. For isothermal crystallization, the crystallization rates of PLA/GO nanocomposites were significantly higher than that of neat PLA, in which t 0.5 reduced from 9.0 to 2.8. Spindle-like nanopores (about 100-200 nm) that arranged like spherulites were prepared by low temperature foaming. It was found that the crystallization rate increase and spherulite morphology change were insignificant when the content of GO exceeded 0.5 wt%, because the excessive GO increased the number of nucleation sites while restricting the PLA crystal growth. Thus, the arrangement of nanopores did not mimick the spherulites because of imperfect crystal morphology.

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“…Using lower temperatures effectively increases the solubility, resulting in a larger number of nucleation sites for pore formation affording smaller pore size and higher pore density. Additionally, faster depressurization generates smaller pore size and higher pore density . Recent advancement in the one‐step batch foaming techniques stemmed from the development of a new autoclave with the capability to achieve very fast depressurization rates.…”

Section: Structure–property Relationships Of Nanoporous Foamsmentioning

confidence: 99%

“…Unlike the one‐step foaming, which requires the use of a plasticizable polymer that forms a rubbery state upon saturation, a larger variety of polymers utilize the two‐step foaming procedure to form microporous structures. The downfall of this procedure occurs with the added cost of the second processing step . A fewer number of groups have demonstrated successful formation of nanoporous materials using the two‐step method.…”

Section: Structure–property Relationships Of Nanoporous Foamsmentioning

confidence: 99%

Advanced Polymers for Reduced Energy Consumption in Architecture

Heifferon

Long

2018

Macromol. Rapid Commun.

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In an effort to slow the progress of climate change, the current scientific community has focused on the reduction of greenhouse gases in order to limit the global average temperature inflation to less than 2 °C. The improvement of thermally controlled construction materials can potentially result in lower energy homes/reduced emissions, and lowering the thermal conductivity of insulation materials improves home energy efficiency. Nanoporous insulation foams impart a drastic decrease in thermal conductivity but many polymer properties must be assessed to produce these materials. Passive phase‐change materials also represent another key energy‐saving device to control heat flux within a living space. Research into unique polymeric systems provides a novel means of encapsulation or creating polymeric cross‐linked matrices to prevent leakage and improve mechanical robustness. These two areas of polymer research in architecture represent key advancements for construction materials aimed toward energy savings and energy‐related emissions control.

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Micro and nano cellular amorphous polymers (PMMA, PS) in supercritical CO2 assisted by nanostructured CO2-philic block copolymers – One step foaming process

Cited by 84 publications

References 40 publications

Bubble nucleation in polymer–CO2 mixtures

Bubble nucleation in polymer–CO2 mixtures

Investigation of poly(l-lactic acid)/graphene oxide composites crystallization and nanopore foaming behaviors via supercritical carbon dioxide low temperature foaming

Advanced Polymers for Reduced Energy Consumption in Architecture

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