scholarly journals Preparation of Microcellular Foams by Supercritical Carbon Dioxide: A Case Study of Thermoplastic Polyurethane 70A

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1650
Author(s):  
Yu-Ting Hsiao ◽  
Chieh-Ming Hsieh ◽  
Tsung-Mao Yang ◽  
Chie-Shaan Su
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Pore Size ◽  
Cell Density ◽  
Thermoplastic Polyurethane ◽  
Saturation Pressure ◽  
Saturation Temperature ◽  
Expansion Ratio ◽  
Microcellular Foam

In this study, a case study to produce microcellular foam of a commercial thermoplastic polyurethane (TPU) through the supercritical carbon dioxide (CO2) foaming process is presented. To explore the feasibility of TPU in medical device and biomedical application, a soft TPU with Shore hardness value of 70A was selected as the model compound. The effects of saturation temperature and saturation pressure ranging from 90 to 140 °C and 90 to 110 bar on the expansion ratio, cell size and cell density of the TPU foam were compared and discussed. Regarding the expansion ratio, the effect of saturation temperature was considerable and an intermediate saturation temperature of 100 °C was favorable to produce TPU microcellular foam with a high expansion ratio. On the other hand, the mean pore size and cell density of TPU foam can be efficiently manipulated by adjusting the saturation pressure. A high saturation pressure was beneficial to obtain TPU foam with small mean pore size and high cell density. This case study shows that the expansion ratio of TPU microcellular foam could be designed as high as 4.4. The cell size and cell density could be controlled within 12–40 μm and 5.0 × 107–1.3 × 109 cells/cm3, respectively.

The Preparation of Microcellular Foam PP Reflective Film

2012 ◽  
Vol 468-471 ◽  
pp. 1078-1081
Author(s):  
Zhen Jiang Shi ◽  
Sheng Lin Yang ◽  
Jun Hong Jin ◽  
Guang Li
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Chemical Process ◽  
Volume Expansion ◽  
Saturation Pressure ◽  
Expansion Ratio ◽  
Processing Conditions ◽  
Microcellular Foam ◽  
Foaming Agent ◽  
Foaming Temperature

This work was aimed at manufacturing the microcellular foam polypropylene for the applications of reflective film with chemical foaming agent or supercritical carbon dioxide. The effects of processing conditions such as the composition of foaming agent during chemical process, the foaming temperature and saturation pressure in physical process on the microcellular structures and the reflectivity as well as the volume expansion ratio were investigated.

scholarly journals Foaming Behavior and Microcellular Morphologies of Incompatible SAN/CPE Blends with Supercritical Carbon Dioxide as a Physical Blowing Agent

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 89 ◽  
Author(s):  
Hai-Chen Zhang ◽  
Chun-Na Yu ◽  
Yong Liang ◽  
Gui-Xiang Lin ◽  
Cong Meng
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Pore Size ◽  
Cell Density ◽  
Average Pore Size ◽  
Average Pore ◽  
Chlorinated Polyethylene ◽  
Blowing Agent ◽  
Interconnected Pores ◽  
Supercritical Carbon

The foaming process and cellular morphologies of poly(styrene-co-acrylonitrile) (SAN)/chlorinated polyethylene (CPE) blends with supercritical carbon dioxide (scCO2) as a blowing agent were investigated in this study. As compared to pure SAN foam in the same batch, the foamed blends with various CPE elastomer content had smaller average pore size and larger cell density. This is probably related to the inhibition of bubble growth by elastomer, resulting in poor melt flowability and strong viscoelasticity, and the efficient bubble heterogeneous nucleation caused by numerous phase interfaces inside the incompletely compatible blend system. In addition, many tiny interconnected holes through the pore walls were formed to connect adjacent micropores in foamed blend samples. The formation mechanism of such interconnected pores is probably due to the fracture of stretched melt around the bubble from phase interfaces with weak interactions. These facts suggest an effective path to control pore size, cell density and even interconnected pores of blend foams depends on the compatibility of the blend system and difference in foamability of individual components in supercritical CO2.

Controlled foaming of polycarbonate/polymethyl methacrylate thin film with supercritical carbon dioxide

2016 ◽  
Vol 30 (12) ◽  
pp. 1713-1727 ◽  
Author(s):  
Yuanxiang Luo ◽  
Yajun Ding ◽  
Changchun Wang ◽  
Linghua Tan ◽  
Sanjiu Ying
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Polymethyl Methacrylate ◽  
Saturation Pressure ◽  
Saturation Temperature ◽  
Mean Diameter ◽  
The Mean ◽  
Foaming Temperature ◽  
Supercritical Carbon ◽  
Foaming Time

The polycarbonate (PC)/polymethyl methacrylate (PMMA) (10/90) blends with microcellular foams were prepared by the two-step process using supercritical carbon dioxide as physical foaming agent. The effects of saturation temperature, saturation pressure, foaming temperature, and foaming time on the cell morphology structure were investigated by scanning electron microscopy. The results indicated that the mean diameter of cells in foamed PC/PMMA films decreased with the increment of saturation temperature and saturation pressure but increased with the increment of the foaming time. Moreover, the mean diameter of cells decreased first, but then increased with the increment of the foaming temperature. The cell density ( Nc) increased with the increment of saturation temperature and saturation pressure but decreased with the increment of the foaming time. However, the Nc increased first but then decreased with the increment of the foaming temperature.

Multi-Stage Recycling Induced Morphological Transformations in Solid-State Microcellular Foaming of Polystyrene

2018 ◽  
Vol 37 (3) ◽  
pp. 121-149 ◽  
Author(s):  
Indrajeet Singh ◽  
Abhishek Gandhi ◽  
Manoranjan Biswal ◽  
Smita Mohanty ◽  
S. K. Nayak
Keyword(s):  
Cell Size ◽  
Cell Density ◽  
Saturation Pressure ◽  
Expansion Ratio ◽  
General Purpose ◽  
Microcellular Foam ◽  
Cell Size Distribution ◽  
Microcellular Foaming ◽  
Multi Stage ◽  
Morphological Transformations

In this article, the general-purpose polystyrene was reprocessed four times. The effect of repeated reprocessing of polystyrene on its polymeric properties and on its microcellular, foaming behaviour were investigated. It was observed that reprocessing leads to break of long polymeric chains into short chains, which resulted increment in PDI and MFI. Molecular weight and Glass transition temperature were found to decrease with increasing recycling stages. Reprocessing resulted abruptly decrement in viscosity of neat polystyrene. Effect of reprocessing on foaming behaviour was analysed properly in this report and it was found that reprocessing resulted in improvement in cell sizes and their distribution. A positive effect on expansion ratio was also observed during foaming of reprocessed specimens. Cell density was found to decrease with increasing recycling stages. The effect of saturation pressure and foaming temperature on microcellular foam morphology along with recycling were investigated. Effect of foaming time on cell size, cell size distribution, cell density, expansion ratio and cell wall thickness was investigated.

Foaming behavior of the fluorinated ethylene propylene copolymer assisted with supercritical carbon dioxide

2020 ◽  
pp. 0021955X2096400
Author(s):  
Zi-yin Jiang ◽  
Yun-fei Zhang ◽  
Chang-jing Gong ◽  
Zhen Yao ◽  
Abhinaya Shukla ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Saturation Pressure ◽  
Nucleating Agent ◽  
Expansion Ratio ◽  
Cell Diameter ◽  
Ethylene Propylene ◽  
Foaming Behavior ◽  
Fluorinated Ethylene Propylene ◽  
Supercritical Carbon

Foaming behavior of the fluorinated ethylene propylene copolymer (FEP) and its composites assisted with supercritical carbon dioxide (scCO2) as the blowing agent were investigated. The batch foaming process was applied at temperature ranging from 250°C to 265°C and pressure ranging between 12 MPa and 24 MPa. The optimal foaming temperature and saturation pressure were obtained for both pure FEP and FEP composites with 1 wt% different-sized BaTiO3 as nucleating agent. The cell diameter of pure FEP foam ranging from 80–140 µm was observed while the cell diameter decreased to 20–40 µm after adding BaTiO3 particles. The cell density of foamed FEP with BaTiO3 increased significantly from 106 to 108 cells/cm3 and the expansion ratio ranged between 4.0 and 5.5. Moreover, a decrease in an abnormal phenomenon that expansion ratio for the pure FEP foam was observed as the saturation pressure increased. This unexpected phenomenon can be explained by the relationship between foaming and crystallization coupling processes.

Solubility and diffusivity of supercritical carbon dioxide in cellulose acetate with cosolvents

2016 ◽  
Vol 49 (1) ◽  
pp. 23-36 ◽  
Author(s):  
Yajun Ding ◽  
Rongjun Wei ◽  
Sanjiu Ying
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cellulose Acetate ◽  
Initial Period ◽  
Saturation Pressure ◽  
Saturation Temperature ◽  
Electron Microscopic ◽  
Cell Nucleation ◽  
Cell Densities ◽  
Supercritical Carbon

The gravimetric procedure was applied to investigate the solubility and diffusivity of supercritical carbon dioxide (SC-CO2) in cellulose acetate (CA). The solubility increases constantly in the initial period and reaches the dissolution equilibrium when the saturation time exceeds 10 h. The solubility decreases gradually from 14.29 wt% to 7.36 wt%, while the saturation temperature increases from 40°C to 70°C. The solubility increases by only 5.63%, while the saturation pressure grows from 10 MPa (12.62 wt%) to 30 MPa (13.33 wt%). The presence of cosolvents, especially ethanol, improves the solubility obviously. The diffusivity is not affected by pressure but increases with the solubility. Scanning electron microscopic images show that the cell densities increase with the content of ethanol, which implies that the higher solubility is in favor of the cell nucleation. The foamed CA with 10 wt% or 20 wt% ethanol has both low density and good impact properties.

scholarly journals Polysulfone foam with high expansion ratio prepared by supercritical carbon dioxide assisted molding foaming method

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 2880-2886 ◽  
Author(s):  
Zhengkun Li ◽  
Yingbin Jia ◽  
Shibing Bai
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
High Performance ◽  
Expansion Ratio ◽  
Supercritical Carbon

Polysulfone foam with high expansion ratio and high performance was prepared by new foaming method using CO2 and press vulcanizer.

scholarly journals Tinjauan karakteristik foam plastik mikroseluler polistirena dengan penambahan aditif pada teknologi superkritis

2018 ◽  
Vol 9 (1) ◽  
pp. 33
Author(s):  
Faidliyah Nilna Minah ◽  
Firman Kurniawansyah ◽  
S Sumarno
Keyword(s):  
Carbon Dioxide ◽  
Cell Density ◽  
Supercritical Co2 ◽  
Cell Diameter ◽  
Coconut Fiber ◽  
Microcellular Foam ◽  
Fiber System ◽  
Average Cell ◽  
Blowing Agent ◽  
Scanning Electron

Processing technology of microcellular plastic represents development of foaming conventional plastic process. The processing of microcellular plastic has been acknowledged as eco-friendly technology because this plastic is produced by the use of benign supercritical carbon dioxide gas as blowing agent. In this work, the samples polystyrene and additive were saturated with supercritical CO2 at various saturation pressures from 10-22 MPa (at around glass transition temperature of 95 oC and 80 oC) When the saturation time was accomplished, the solution was decompressed rapidly into atmospheric pressure. The samples were placed in the vessel heated and completed by flowing of carbon dioxide as cooler gas into the vessel. The samples were characterized to observe volume expansion ratio, cell density, average cell diameter and surface fractured with Scanning Electron Microscopy. The microcellular foam of plastic product of PS system has cell diameter between 3.970-9.933 μm , cell density between 9.14x104 – 6.24x109 cell/ cm3. PS-CaCO3 system has cell diameter between 3.501-8.050 μm, cell density between 3.31x107 – 1.10x1011 cell/cm3, while PS-coconut fiber system hascell diameter between 2.520-8.414 μm, cell density between 1.50x108 -1.60x1010 cell/cm3 at various pressure.Keywords: polystyrene, microcellular foam plastic, supercritical CO2, CaCO3additive, coconut fiber additive.  AbstrakProses pembuatan plastik mikroseluler merupakan pengembangan dari proses pembuatan foam plastik konvensional. Plastik mikroseluler menggunakan fluida superkritis seperti CO2 dan N2 sebagai blowing agent yang ramah terhadap lingkungan, sehingga proses pembuatan foam plastik mikroseluler dikenal sebagai teknologi ramah lingkungan. Penelitian ini menggunakan sampel polistirena yang dicampur dengan partikel kalsium karbonat atau sabut kelapa dengan konsentrasi 5% yang diproses pada kondisi tekanan 10-22 MPa (T = 95 oC dan 80 oC). Setelah kondisi yang diinginkan tercapai dilakukan dekompresi secara mendadak menuju tekanan atmosfer, dan dilanjutkan dengan proses pemanasan, diakhiri dengan mengalirkan gas CO2 sebagai pendingin. Selanjutnya sampel dikarakterisasi untuk mengetahui rasio volume ekspansi foam, densitas sel, diameter rata-rata sel dan struktur foam yang dihasilkan dengan Scanning Electron Microscope. Pada penelitian ini didapatkan pada sistem PS Murni menghasilkan diameter sel antara 3,970-9,933 μm dan densitas sel 9,14x104 - 6,24x109 cell/cm3. Sistem PS-CaCO3 menghasilkan diameter sel antara 3,501-8,050 μm dan densitas sel 3,31x107 - 1,10x1011 cell/cm3, dan pada sistem PS-Sabut kelapa menghasilkan diameter sel antara 2,520-8,414 μm dan densitas sel 1,50x108 - 1,60x1010 cell/cm3 pada berbagai variasi tekanan.Kata kunci : polistirena, foam plastik mikroseluler, CO2 superkritis, aditif CaCO3, aditif sabut kelapa.

Research on the Effect of Supercritical Carbon Dioxide on the Properties of Super Heavy Oil

2011 ◽  
Vol 347-353 ◽  
pp. 1689-1695
Author(s):  
Zhao Min Li ◽  
Wei Liu ◽  
Song Yan Li ◽  
Jing Li ◽  
Bin Fei Li
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heavy Oil ◽  
Saturation Pressure ◽  
Oil Field ◽  
Viscosity Reduction ◽  
Oil Reservoir ◽  
Volume Factor ◽  
Heavy Oil Reservoir ◽  
Supercritical Carbon

Carbon dioxide flooding is an important way to exploit heavy oil reservoir. Considering the Zheng411 super heavy oil reservoir in Shengli Oil Field, the solubility of supercritical carbon dioxide in super heavy oil, and the effect of supercritical carbon dioxide on the volume factor, viscosity, component content and oil/water emulsification of super heavy oil are researched. The result shows: the solubility of carbon dioxide in super heavy oil increases with the increasing pressure, but the increasing extent declines gradually, when the pressure is below 28MPa, the solubility of carbon dioxide decreases with the rising temperature under the same saturation pressure; the volume factor increases linearly with the increase of supercritical carbon dioxide solubility; under the condition of unsaturation, the supercritical carbon dioxide is able to reduce the density of super heavy oil substantially, whereas it has little impact on the chemical properties of oil; Demulsification and visbreaking can be realized through dissolving supercritical carbon dioxide in super heavy oil that contains water, and the viscosity reduction capacity of carbon dioxide is hardly affected by water.

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