Investigation of the nanocellular foaming of polystyrene in supercritical CO<sub>2</sub> by adding a CO<sub>2</sub>‐philic perfluorinated block copolymer

Ruiz, José A. Reglero; Cloutet, Éric; Dumon, Michel

doi:10.1002/app.36455

Cited by 22 publications

(10 citation statements)

References 40 publications

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“…These results corroborate the nucleation efficiency values presented in Figure , which show a sudden increase for particles larger than 40 nm when the contact angle for nucleation is low, that is, for the particles with a PDMS shell, whereas for the bare silica particles, there is a more steady increase of the nucleation efficiency. Interesting to mention here is that CO 2 -philic block copolymer-based heterogeneous phases are considered as promising nucleation agents, as well. ,, In fact, Rodriguez-Perez and co-workers reported a nucleation efficiency close to unity for poly(methyl methacrylate)- co -poly(butyl acrylate)- co -poly(methyl methacrylate) block copolymer (BCP) domains in PMMA. This high nucleation efficiency could be explained by the fact that depending on the nucleation point in the phase-separated morphologies of the BCPs, these block copolymer domains do not experience a line tension.…”

Section: Results and Discussionmentioning

confidence: 99%

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Liu

Eijkelenkamp

Duvigneau

et al. 2017

ACS Appl. Mater. Interfaces

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Core–shell nanoparticles consisting of silica as core and surface-grafted poly(dimethylsiloxane) (PDMS) as shell with different diameters were prepared and used as heterogeneous nucleation agents to obtain CO2-blown poly(methyl methacrylate) (PMMA) nanocomposite foams. PDMS was selected as the shell material as it possesses a low surface energy and high CO2-philicity. The successful synthesis of core–shell nanoparticles was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. The cell size and cell density of the PMMA micro- and nanocellular materials were determined by scanning electron microscopy. The cell nucleation efficiency using core–shell nanoparticles was significantly enhanced when compared to that of unmodified silica. The highest nucleation efficiency observed had a value of ∼0.5 for nanoparticles with a core diameter of 80 nm. The particle size dependence of cell nucleation efficiency is discussed taking into account line tension effects. Complete engulfment by the polymer matrix of particles with a core diameter below 40 nm at the cell wall interface was observed corresponding to line tension values of approximately 0.42 nN. This line tension significantly increases the energy barrier of heterogeneous nucleation and thus reduces the nucleation efficiency. The increase of the CO2 saturation pressure to 300 bar prior to batch foaming resulted in an increased line tension length. We observed a decrease of the heterogeneous nucleation efficiency for foaming after saturation with CO2 at 300 bar, which we attribute to homogenous nucleation becoming more favorable at the expense of heterogeneous nucleation in this case. Overall, it is shown that the contribution of line tension to the free energy barrier of heterogeneous foam cell nucleation must be considered to understand foaming of viscoelastic materials. This finding emphasizes the need for new strategies including the use of designer nucleating particles to enhance the foam cell nucleation efficiency.

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Section: Results and Discussionmentioning

confidence: 99%

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Liu

Eijkelenkamp

Duvigneau

et al. 2017

ACS Appl. Mater. Interfaces

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“…Polymers with a higher maximum CO 2 solubility theoretically induce smaller pore morphologies at easier processing conditions (lower pressure). Other methods, such as the addition of polar fluorine atoms, also enhance solubility in microporous foams, but currently do not make an appearance in their nanoporous counterparts with the exception of their addition into block‐copolymers …”

Section: Structure–property Relationships Of Nanoporous Foamsmentioning

confidence: 99%

“…Other methods, such as the addition of polar fluorine atoms, also enhance solubility in microporous foams, but currently do not make an appearance in their nanoporous counterparts with the exception of their addition into block-copolymers. [42,43] In situations, such as PET, where both phenyl rings and carbonyls are present, the susceptibility to assume that an increase in solubility would occur comes easily. Unfortunately, the crystallizability of PET significantly reduces the overall solubility and negates the benefits of both interactions, which negates this assumption.…”

Section: Effect Of Co 2 Solubilitymentioning

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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“…Currently, five kinds of polymers could be employed to prepare nanocellular foam: amorphous polymer, 8 acrylic copolymer, 15 block copolymer with a high CO 2 -philic nano-sized dispersed phase segments, 16 polymer blend-containing nano-templates, 17 and polymer composites. 18 Amorphous polymers with an extremely large viscoelasticity could significantly restrict cell growth and coalescence.…”

Section: Introductionmentioning

confidence: 99%

Nanocellular Foaming Behaviors of Chain-Extended Poly(lactic acid) Induced by Isothermal Crystallization

et al. 2019

ACS Omega

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Recently, the fabrication of semicrystalline polymer foams with a nanocellular structure by supercritical fluids has been becoming a newly developing research hotspot, owing to their peculiar properties and prospective applications. In this work, a facile and effective isothermal crystallization-induced method was proposed to prepare nanocellular semicrystalline poly(lactic acid) (PLA) foams using CO 2 as a physical blowing agent. Styrene–acrylonitrile–glycidyl methacrylate (SAG) as a chain extender (CE) was introduced into PLA through a melt-mixing method to improve the crystallization behavior and melt viscoelasticity of PLA. The chain extension reaction between PLA and SAG occurred successfully as well as the branching and micro cross-linking structures were generated in chain-extended PLA (CPLA) samples, which were confirmed by Fourier transform infrared spectra, gel fraction, and intrinsic viscosity measurements. Owing to the nucleation effect of branching points and the restricted movement of PLA molecular chains by the formation of branching and/or microcross-linking structures, a large number of small spherocrystals were generated in CPLA samples, which was beneficial to produce nanocells. Nanocellular CPLA foams were prepared successfully, when the foaming temperature was 125 °C. As the SAG content increased, the cell size of various PLA foams decreased from 364 ± 198 to 249 ± 100 nm and their volume expansion ratio increased from 1.15 ± 0.05 to 2.22 ± 0.01 times, gradually. When the foaming temperature increased from 125 to 127 °C, an interesting transition from nanocells to microcells could be observed in CPLA foam with the CE content of 2 wt %. Finally, the formation mechanism of nanocells in various PLA foams was proposed and clarified using a schematic diagram.

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Investigation of the nanocellular foaming of polystyrene in supercritical CO₂ by adding a CO₂‐philic perfluorinated block copolymer

Cited by 22 publications

References 40 publications

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Advanced Polymers for Reduced Energy Consumption in Architecture

Nanocellular Foaming Behaviors of Chain-Extended Poly(lactic acid) Induced by Isothermal Crystallization

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Investigation of the nanocellular foaming of polystyrene in supercritical CO2 by adding a CO2‐philic perfluorinated block copolymer

Cited by 22 publications

References 40 publications

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Silica-Assisted Nucleation of Polymer Foam Cells with Nanoscopic Dimensions: Impact of Particle Size, Line Tension, and Surface Functionality

Advanced Polymers for Reduced Energy Consumption in Architecture

Nanocellular Foaming Behaviors of Chain-Extended Poly(lactic acid) Induced by Isothermal Crystallization

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Investigation of the nanocellular foaming of polystyrene in supercritical CO₂ by adding a CO₂‐philic perfluorinated block copolymer