Preparation and Characterization of Foaming Poly (phenylene ether ketone) PPEK by Using Supercritical Carbon Dioxide

2013 ◽  
Vol 423-426 ◽  
pp. 519-522
Author(s):  
Min Jie Qu ◽  
Shi Yang Zhu ◽  
Lai Jiu Zheng ◽  
Tian Qi Li ◽  
Ling Ling He ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cell Size ◽  
Cell Density ◽  
Cell Morphology ◽  
Positive Impact ◽  
Process Conditions ◽  
Ether Ketone ◽  
Foaming Temperature

This paper presents foaming behaviors of PPEK blown with supercritical CO2. The cell density and cell size of PPEK at various process conditions were studied. The experimental results indicate that saturate pressure, foaming temperature and suitable foaming time can provide a positive impact on improving the cell morphology of PPEK foams.

Cell characteristics of epoxy resin foamed by step temperature-rising process using supercritical carbon dioxide as blowing agent

2016 ◽  
Vol 54 (2) ◽  
pp. 359-377 ◽  
Author(s):  
Jiaxun Lyu ◽  
Tao Liu ◽  
Zhenhao Xi ◽  
Ling Zhao
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Epoxy Resin ◽  
Cell Size ◽  
Cell Density ◽  
Diglycidyl Ether ◽  
Bubble Nucleation ◽  
Blowing Agent ◽  
Curing Reaction ◽  
Supercritical Carbon

A temperature-rising batch foaming process with supercritical carbon dioxide (ScCO2) as blowing agent was used to prepare epoxy resin foams consisting of diglycidyl ether of bisphenol A and m-xylylenediamine. The dissolution and diffusion behaviors of CO2 in pre-cured epoxy resin were investigated, as well as the parameter effect of CO2 saturation step and foaming step on the cell characteristics. It was proved that closed-cells could be generated for CO2 unsaturated samples and the cell characteristics with the same dissolved CO2 concentration were similar. The merged and cracked bubble morphologies were usually obtained for CO2-saturated epoxy resin samples. With increasing CO2 concentration from 0.021 g CO2/g epoxy resin to 0.061 g CO2/g epoxy resin in the unsaturated samples, the cell size increased from 170.2 µm to 262.6 µm and the cell density decreased from 6.8 × 105/cm3 to 3.1 × 105/cm3. Bubble nucleation and growth occurred simultaneously with curing reaction in temperature-rising step. As the final foaming temperature increased from 60℃ to 120℃, the cell size of samples with dissolved CO2 concentration of 0.021 g CO2/g epoxy resin increased from 172.7 µm to 369.0 µm, while the cell density first increased from 6.8 to 7.3 and then decreased to 3.5. The cell size of samples with CO2 concentration of 0.031 g CO2/g epoxy resin increased from 145.3 µm to 180.5 µm with foaming time from 5 min to 20 min, but changed slightly when curing reaction almost finished and CO2 was depleted after 20 min.

Key Parameters Influencing Microcellular Polystyrene Cell Morphology Blowing with Supercritical CO2

2012 ◽  
Vol 501 ◽  
pp. 237-242 ◽  
Author(s):  
Chang Yun Gao ◽  
Nan Qiao Zhou ◽  
Ti Kun Shan ◽  
Zhen Xiang Xin
Keyword(s):  
Size Distribution ◽  
Cell Size ◽  
Cell Density ◽  
Cell Morphology ◽  
Saturation Pressure ◽  
Processing Temperature ◽  
Polymer Foam ◽  
Cell Size Distribution ◽  
Average Cell ◽  
Foaming Temperature

Polystyrene microcellular foams blowing with supercritical CO2 were prepared with a novel polymer foam processing simulator. Key parameters influencing Polystyrene cell morphology were investigated. The effect of processing temperature and saturation pressure on cell morphology was observed by scanning electron microscope and the average cell diameter and cell size distribution was calculated. The results show that the cell density decrease and cell size increase with the increase of foaming temperature. The cell density increase and cell size decrease with the increase of saturation pressure. And the cell size distribution shows a narrow distribution at lower foaming temperature and higher saturation pressure.

Preparation and characterization of polypropylene/waste ground rubber tire powder microcellular composites by supercritical carbon dioxide

2008 ◽  
Vol 16 (5) ◽  
pp. 404-410 ◽  
Author(s):  
Zhen Xiu Zhang ◽  
Sung Hyo Lee ◽  
Jin Kuk Kim ◽  
Shu Ling Zhang ◽  
Zhen Xiang Xin
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Rubber Tire ◽  
Ground Rubber ◽  
Supercritical Carbon

scholarly journals Synthesis of Supported Heterogeneous Catalysts by Laser Ablation of Metallic Palladium in Supercritical Carbon Dioxide Medium

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5807
Author(s):  
Oleg Parenago ◽  
Alexey Rybaltovsky ◽  
Evgeniy Epifanov ◽  
Andrey Shubnyi ◽  
Galina Bragina ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Laser Ablation ◽  
Supercritical Carbon Dioxide ◽  
Heterogeneous Catalysts ◽  
Mixing Time ◽  
Laser Wavelength ◽  
Process Conditions ◽  
Metallic Palladium ◽  
Palladium Particles ◽  
Supercritical Carbon

To obtain a supported heterogeneous catalyst, laser ablation of metallic palladium in supercritical carbon dioxide was performed in the presence of a carrier, microparticles of γ-alumina. The influence of the ablation process conditions—including supercritical fluid density, ablation, mixing time of the mixture, and laser wavelength—on the completeness and efficiency of the deposition of palladium particles on the surface of the carrier was studied. The obtained composites were investigated by scanning and transmission electron microscopy using energy dispersive spectroscopy. We found that palladium particles were nanosized and had a narrow size distribution (2–8 nm). The synthesized composites revealed high activity as catalysts in the liquid-phase hydrogenation of diphenylacetylene.

scholarly journals Controlling Foam Morphology of Poly(methyl methacrylate) via Surface Chemistry and Concentration of Silica Nanoparticles and Supercritical Carbon Dioxide Process Parameters

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Deniz Rende ◽  
Linda S. Schadler ◽  
Rahmi Ozisik
Keyword(s):  
Carbon Dioxide ◽  
Surface Modification ◽  
Supercritical Carbon Dioxide ◽  
Surface Chemistry ◽  
Silica Nanoparticles ◽  
Process Parameters ◽  
Process Conditions ◽  
Average Cell ◽  
Foam Morphology ◽  
Supercritical Carbon

Polymer nanocomposite foams have received considerable attention because of their potential use in advanced applications such as bone scaffolds, food packaging, and transportation materials due to their low density and enhanced mechanical, thermal, and electrical properties compared to traditional polymer foams. In this study, silica nanofillers were used as nucleating agents and supercritical carbon dioxide as the foaming agent. The use of nanofillers provides an interface upon which CO2nucleates and leads to remarkably low average cell sizes while improving cell density (number of cells per unit volume). In this study, the effect of concentration, the extent of surface modification of silica nanofillers with CO2-philic chemical groups, and supercritical carbon dioxide process conditions on the foam morphology of poly(methyl methacrylate), PMMA, were systematically investigated to shed light on the relative importance of material and process parameters. The silica nanoparticles were chemically modified with tridecafluoro-1,1,2,2-tetrahydrooctyl triethoxysilane leading to three different surface chemistries. The silica concentration was varied from 0.85 to 3.2% (by weight). The supercritical CO2foaming was performed at four different temperatures (40, 65, 75, and 85°C) and between 8.97 and 17.93 MPa. By altering the surface chemistry of the silica nanofiller and manipulating the process conditions, the average cell diameter was decreased from9.62±5.22to1.06±0.32 μm, whereas, the cell density was increased from7.5±0.5×108to4.8±0.3×1011cells/cm3. Our findings indicate that surface modification of silica nanoparticles with CO2-philic surfactants has the strongest effect on foam morphology.

Characterization of drug delivery particles produced by supercritical carbon dioxide technologies

2017 ◽  
Vol 128 ◽  
pp. 244-262 ◽  
Author(s):  
Onanong Nuchuchua ◽  
M. Reza Nejadnik ◽  
Sebastiaan C. Goulooze ◽  
Nataša Jovanović Lješković ◽  
Hayley A. Every ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Drug Delivery ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Carbon

scholarly journals Effect of CO2 Preservation Treatments on the Sensory Quality of Pomegranate Juice

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5598
Author(s):  
Ana Carolina Mosca ◽  
Leonardo Menghi ◽  
Eugenio Aprea ◽  
Maria Mazzucotelli ◽  
Jose Benedito ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Co2 ◽  
Sensory Quality ◽  
Pomegranate Juice ◽  
Process Conditions ◽  
Volatile Profile ◽  
Projective Mapping ◽  
Supercritical Carbon

Due to the interest in identifying cost-effective techniques that can guarantee the microbiological, nutritional, and sensorial aspects of food products, this study investigates the effect of CO2 preservation treatment on the sensory quality of pomegranate juice at t0 and after a conservation period of four weeks at 4 °C (t28). The same initial batch of freshly squeezed non-treated (NT) juice was subjected to non-thermal preservation treatments with supercritical carbon dioxide (CO2), and with a combination of supercritical carbon dioxide and ultrasound (CO2-US). As control samples, two other juices were produced from the same NT batch: A juice stabilized with high pressure treatment (HPP) and a juice pasteurized at high temperature (HT), which represent an already established non-thermal preservation technique and the conventional thermal treatment. Projective mapping and check-all-that-apply methodologies were performed to determine the sensory qualitative differences between the juices. The volatile profile of the juices was characterized by gas chromatography-mass spectrometry. The results showed that juices treated with supercritical CO2 could be differentiated from NT, mainly by the perceived odor and volatile compound concentration, with a depletion of alcohols, esters, ketones, and terpenes and an increase in aldehydes. For example, in relation to the NT juice, limonene decreased by 95% and 90%, 1-hexanol decreased by 9% and 17%, and camphene decreased by 94% and 85% in the CO2 and CO2-US treated juices, respectively. Regarding perceived flavor, the CO2-treated juice was not clearly differentiated from NT. Changes in the volatile profile induced by storage at 4 °C led to perceivable differences in the odor quality of all juices, especially the juice treated with CO2-US, which underwent a significant depletion of all major volatile compounds during storage. The results suggest that the supercritical CO2 process conditions need to be optimized to minimize impacts on sensory quality and the volatile profile.

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