An overview of polymer foaming assisted by supercritical fluid

Dong, Mengyao; Wang, Gang; Zhang, Xiangning; Tan, Daqing; D, Jaya Prasanna Kumar; Ren, Juanna; Colorado, Henry; Hou, Hua; Toktarbay, Zhexenbek; Guo, Zhanhu

doi:10.1007/s42114-023-00790-6

Cited by 23 publications

(3 citation statements)

References 195 publications

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“…It is known that the uneven stress release in a polymer matrix or bilayer polymer film may cause the distortion of the surface layer and the formation of microwrinkles. , The rapid expansion and contraction of TPU during scCO 2 foaming is also capable of generating microsized wrinkles. ,− In dynamic scCO 2 foaming that involves a constant scCO 2 flow field, high-density fine wrinkles can be obtained in a one-step process . In this work, the wrinkled TPU surfaces were fabricated via dynamic scCO 2 foaming at varying scCO 2 flow rates (e.g., 18, 27, and 36 mL/min) (Figure S11).…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field

Cui,

Zhou,

et al. 2024

Macromolecules

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The external force field has a profound influence on the molecular structure and properties of polymers, but the effect of the supercritical carbon dioxide (scCO 2 ) flow field on the molecular dynamics (MD) of thermoplastic polyurethane (TPU) remains uncharted. We previously discovered the formation of wrinkled structures in TPU during scCO 2 foaming in the presence of a scCO 2 flow field, but the underlying mechanism is elusive. In this work, the flow-induced orientation of TPU molecular chains and the subsequent chain relaxation when the flow field is removed are systematically investigated with nonequilibrium molecular dynamics simulations. The orientation and stretching of molecular chains intensified with an increasing shear rate (Wi), which led to increases in internal stress and kinetic energy. Although TPU chains reached similar orientation conformations under various Wi, the internal stress and orientation speed are higher in the case of high Wi. In the relaxation process, the molecular chains that are stretched at a higher Wi exhibited faster stress release and conformation disordering, which caused a smaller radius of gyration (R g ) and higher stress level compared to the initial coiled state. This fast stress relaxation behavior is believed to be responsible for the formation of fine and dense wrinkles on the TPU surface. The molecular insight from our simulations reveals the wrinkle formation mechanism and is meaningful for controlling the microstructure and properties of wrinkled TPUs.

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Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field

Cui,

Zhou,

et al. 2024

Macromolecules

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“…The excellent mechanical properties of polymers and the possibility of shaping their structural characteristics during processing − make them attractive alternatives for the targeted applications. Notably, poly(oxymethylene) (POM), an engineering thermoplastic, exhibits excellent mechanical properties, especially after stretching, owing to its high crystallinity and propensity to form oriented lamellae interconnected by amorphous tie chains .…”

Section: Introductionmentioning

confidence: 99%

Electrospun Materials with High Reflectance and Polarization Contrast for Sensing Applications in the Mid-Infrared Atmospheric Window

Laramée,

Roy,

Pellerin

2024

ACS Appl. Polym. Mater.

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Several applications in remote sensing and thermal management require materials with high reflectivity and polarization contrast in the mid-infrared (MIR) spectral range. However, the existing options often fall short in terms of mechanical properties and practicality, especially for field deployment. To address this challenge, we leverage the polaritonic response of poly(oxymethylene) (POM) and the anisotropy induced by electrospinning to produce robust POM fiber mats with high reflectance and polarization contrast in the MIR atmospheric window. Specular reflection IR spectroscopy demonstrates that the optical properties can be optimized by a series of mat post-treatments, namely submersion with a nonsolvent, incorporation of an indexmatching medium, drawing, and compression, which were applied iteratively to refine the optical response. The optimized mats achieve a maximum reflectance of 60 ± 8% and a corresponding polarization contrast (degree of linear polarization) of 0.52 ± 0.01. Importantly, the formulated materials remain flexible and generally retain appropriate optical properties under long-term storage and when exposed to harsh simulated operational conditions. As a result, they are considered promising target substrates for the development, testing, and field deployment of advanced MIR polarimetric remote sensors.

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“…To achieve polyether-based ICE with excellent mechanical properties, hard polymer segments were usually integrated for copolymerization with polyether. − However, the presence of chemical cross-links in polyether-based ICE containing hard polymer segments prevented thermoplastic processing, leading to low productivity. Additionally, the extensive use of solvents in preparing these polyether-based ICE made the process environmentally unfriendly and costly. − Thermoplastic molding methods such as injection molding, extrusion molding, and supercritical foaming molding offer advantages including continuous production capability, high molding efficiency and cost-effectiveness. − Therefore, a critical challenge was to develop ionic conductive elastomers free from solvents, ensuring both excellent comprehensive performance and high productivity.…”

Section: Introductionmentioning

confidence: 99%

Robust and Highly Stretchable Ionic Conductive Thermoplastic Elastomers for Wearable Electronics

Yan,

Fan,

et al. 2024

ACS Appl. Polym. Mater.

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With the rapid advancement of artificial intelligence, there has been a surge of enthusiasm for flexible ionic conductors suitable for use in human−computer interaction. Complex preparation processes, difficulties to being efficiently molded, and disability in rapid integration are the main challenges faced by flexible ionic conductors in practical application. In this study, a simple, facile, and environmentally friendly approach involving melt transesterification and melt blending has been developed to produce ultrastretchable, highly ionically conductive, and easily processable poly(butylene succinate)-block-polyethylene glycol/propylene carbonate/sodium thiocyanate (PBS-b-PEG/PC/NaSCN) blendbased ionic conductive thermoplastic elastomers (ICTEs). Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier infrared spectroscopy (FTIR) revealed that the excellent ionic conductivity of the ICTE could be attributed to the synergistic effects of poly(butylene succinate) (PBS) segments and propylene carbonate (PC) in constructing ionic conductive channels in the ICTE. The ICTE exhibited a tensile strength of 8.3 MPa and an elongation of 1790%, making it suitable for use in wearable devices. Based on its outstanding processability, shape stability at high temperatures, thermal stability during processing, and constant sensing performance, an ICTE-based fabric sensor was successfully fabricated using the melt spinning and weaving technique. This fabric sensor effectively demonstrated its capability to monitor human activities.

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An overview of polymer foaming assisted by supercritical fluid

Cited by 23 publications

References 195 publications

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field

Electrospun Materials with High Reflectance and Polarization Contrast for Sensing Applications in the Mid-Infrared Atmospheric Window

Robust and Highly Stretchable Ionic Conductive Thermoplastic Elastomers for Wearable Electronics

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An overview of polymer foaming assisted by supercritical fluid

Cited by 23 publications

References 195 publications

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO2 Flow Field

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO2 Flow Field

Electrospun Materials with High Reflectance and Polarization Contrast for Sensing Applications in the Mid-Infrared Atmospheric Window

Robust and Highly Stretchable Ionic Conductive Thermoplastic Elastomers for Wearable Electronics

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Product

Resources

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Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field

Molecular Dynamics Simulations and Mechanistic Insights into Wrinkle Formation in TPU under Supercritical CO₂ Flow Field