Supercritical CO2 deposition and foaming process for fabrication of biopolyester-ZnO bone scaffolds

2017 ◽  
Vol 135 (7) ◽  
pp. 45824 ◽  
Author(s):  
Jasna Ivanovic ◽  
Kurosch Rezwan ◽  
Stephen Kroll
Keyword(s):  
Supercritical Co2 ◽  
Bone Scaffolds ◽  
Foaming Process

scholarly journals High Performance Attapulgite/Polypyrrole Nanocomposite Reinforced Polystyrene (PS) Foam Based on Supercritical CO2 Foaming

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 985 ◽  
Author(s):  
Yidong Liu ◽  
Lingfeng Jian ◽  
Tianhua Xiao ◽  
Rongtao Liu ◽  
Shun Yi ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
High Performance ◽  
In Situ Polymerization ◽  
Compression Modulus ◽  
Blowing Agents ◽  
Foaming Process ◽  
Potential Applications ◽  
Polymerization Method ◽  
Low Solubility

CO2 has been regarded as one of the most promising blowing agents for polystyrene (PS) foam due to its non-flammability, low price, nontoxicity, and eco-friendliness. However, the low solubility and fast diffusivity of CO2 in PS hinder its potential applications. In this study, an attapulgite (ATP)/polypyrrole (PPy) nanocomposite was developed using the in situ polymerization method to generate the hierarchical cell texture for the PS foam based on the supercritical CO2 foaming. The results demonstrated that the nanocomposite could act as an efficient CO2 capturer enabling the random release of it during the foaming process. In contrast to the pure PS foam, the ATP/PPy nanocomposite reinforced PS foam is endowed with high cell density (up to 1.9 × 106) and similar thermal conductivity as the neat PS foam, as well as high compression modulus. Therefore, the in situ polymerized ATP/PPy nanocomposite makes supercritical CO2 foaming desired candidate to replace the widely used fluorocarbons and chlorofluorocarbons as PS blowing agents.

scholarly journals Analysis of Bubble Growth in Supercritical CO2 Extrusion Foaming Polyethylene Terephthalate Process Based on Dynamic Flow Simulation

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2799
Author(s):  
Shun Yao ◽  
Yichong Chen ◽  
Yijie Ling ◽  
Dongdong Hu ◽  
Zhenhao Xi ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Bubble Growth ◽  
Supercritical Co2 ◽  
Flow Simulation ◽  
The Finite Element Method ◽  
Melt Flow ◽  
Dynamic Flow ◽  
Foaming Process ◽  
Dynamic Rheological Properties ◽  
Extrusion Foaming

Bubble growth in the polymer extrusion foaming process occurs under a dynamic melt flow. For non-Newtonian fluids, this work successfully coupled the dynamic melt flow simulation with the bubble growth model to realize bubble growth predictions in an extrusion flow. The initial thermophysical properties and dynamic rheological property distribution at the cross section of the die exit were calculated based on the finite element method. It was found that dynamic rheological properties provided a necessary solution for predicting bubble growth during the supercritical CO2 polyethylene terephthalate (PET) extrusion foaming process. The introduction of initial melt stress could effectively inhibit the rapid growth of bubbles and reduce the stable size of bubbles. However, the initial melt stress was ignored in previous work involving bubble growth predictions because it was not available. The simulation results based on the above theoretical model were consistent with the evolution trends of cell morphology and agreed well with the actual experimental results.

scholarly journals Fabrication of Poly(butylene succinate)/Carbon Black Nanocomposite Foams with Good Electrical Conductivity and High Strength by a Supercritical CO2 Foaming Process

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1852 ◽  
Author(s):  
Zhou Chen ◽  
Junfeng Hu ◽  
Jiajun Ju ◽  
Tairong Kuang
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Supercritical Co2 ◽  
Functional Materials ◽  
High Strength ◽  
Complex Viscosity ◽  
Dynamic Mechanical Properties ◽  
Butylene Succinate ◽  
Foaming Process ◽  
Nanocomposite Foams

Lightweight, high-strength and electrically conductive poly(butylene succinate) (PBS)/ carbon black (CB) nanocomposite foams with a density of 0.107–0.344 g/cm3 were successfully fabricated by a solid-state supercritical CO2 (ScCO2) foaming process. The morphology, thermal and dynamic mechanical properties, and rheological behavior of the PBS/CB nanocomposites were studied. The results indicate that the CB nanofiller was well dispersed in the PBS matrix and the presence of a proper CB nanofiller can accelerate the rate of crystallization, improve the thermal stability, enhance the stiffness, and increase the complex viscosity of PBS/CB nanocomposites. These improved properties were found to play an important role in the foaming process. The results from foaming experiments showed that the PBS/CB nanocomposite foams had a much smaller cell size, a higher cell density, and a more uniform cell morphology as compared to neat PBS foams. Furthermore, the PBS/CB nanocomposite foams also possessed low density (0.107–0.344 g/cm3), good electrical conductivity (~0.45 S/cm at 1.87 vol % CB loading), and improved compressive strength (108% increase), which enables them to be used as lightweight and high-strength functional materials.

scholarly journals Ultrahigh and Tunable Electromagnetic Interference Shielding Performance of PVDF Composite Induced by Nano-Micro Cellular Structure

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 234
Author(s):  
Yang Yang ◽  
Shuiping Zeng ◽  
Xiping Li ◽  
Zhonglue Hu ◽  
Jiajia Zheng
Keyword(s):  
Electromagnetic Interference ◽  
Supercritical Co2 ◽  
Cell Structure ◽  
Vital Role ◽  
Compression Tests ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Polymer Foam ◽  
Emi Shielding Effectiveness ◽  
Foaming Process

Lightweight and efficient electromagnetic interference (EMI) shielding materials play a vital role in protecting high-precision electronic devices and human health. Porous PVDF/CNTs/urchin-like Ni composites with different cell sizes from nanoscale to microscale were fabricated through one-step supercritical carbon dioxide (CO2) foaming. The electrical conductivity and electromagnetic interference (EMI) shielding performance of the composites with different cell sizes were examined in detail. The results indicated that the nanoscale cell structure diminishes the EMI shielding performance of the composite, whereas the microscale cell structure with an appropriate size is beneficial for improving the EMI shielding performance. A maximum EMI shielding effectiveness (SE) of 43.4 dB was achieved by the composite foams which is about twice that of the solid composite. Furthermore, as the supercritical CO2 foaming process reduces the density of the composite by 25–50%, the EMI SSE (specific shielding effectiveness)/t(thickness) of the composite reaches 402 dB/(g/cm2), which is the highest value of polymer foam obtained to the best of the authors’ knowledge. Finally, compression tests were performed to show that the composites still maintained excellent mechanical properties after the supercritical CO2 foaming process.

scholarly journals New insights in the morphological characterization and modelling of poly(ε-caprolactone) bone scaffolds obtained by supercritical CO2 foaming

2020 ◽  
Vol 166 ◽  
pp. 105012 ◽  
Author(s):  
Víctor Santos-Rosales ◽  
Marta Gallo ◽  
Philip Jaeger ◽  
Carmen Alvarez-Lorenzo ◽  
José L. Gómez-Amoza ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Morphological Characterization ◽  
Bone Scaffolds
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