Effect of supercritical carbon dioxide treatment on structure and mechanical properties of β-nucleated polypropylene processed at different temperatures

2017 ◽  
Vol 60 ◽  
pp. 211-219 ◽  
Author(s):  
Chengzhen Geng ◽  
Hongwei Bai ◽  
Qiang Fu ◽  
Feng Luo
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Different Temperatures ◽  
Supercritical Carbon

Enhancement of the Mechanical Properties of PEBAX Graphene Nanocomposite Using Supercritical Fluid Assisted Extrusion Polymer Processing Technique

2017 ◽  
Vol 883 ◽  
pp. 75-84 ◽  
Author(s):  
Nireeksha Karode ◽  
Laurence Fitzhenry ◽  
Siobhán Matthews ◽  
Philip Walsh ◽  
Austin Coffey
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Polymer Processing ◽  
Processing Technique ◽  
Graphene Nanocomposites ◽  
Mechanical Tensile ◽  
Supercritical Carbon

Medical tubing used in minimally invasive devices presents a number of design considerations depending on the material used, design requirements (such as sufficient stiffness, flexibility and biocompatibility) and processing conditions. Currently, manufacturing industries adopt co-extrusion systems to meet design specifications, by using multilayer configuration leading to higher cost per device and increased complexity. This paper investigates the mechanical performance of nanocomposites using supercritical carbon dioxide assisted polymer processing technique. The use of innovative medical compounds such as PEBAX graphene nanocomposites have resulted in measurable improvements in mechanical properties. This study also presents the effect of supercritical carbon dioxide on the mechanical and physical properties of the polymer matrix. The mechanical properties have been investigated using dynamic mechanical analysis (DMA) and mechanical tensile test, where sufficient reinforcement was observed depending on the composition of graphene within PEBAX matrix. ATR-FTIR was used to further analyze the effect of supercritical carbon dioxide and interactions within the polymer composite matrix.

scholarly journals Determination of Oleanolic and Ursolic Acids inHedyotis diffusaUsing Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Ming-Chi Wei ◽  
Yu-Chiao Yang ◽  
Show-Jen Hong
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
High Performance ◽  
Extraction Yield ◽  
Extraction Time ◽  
Different Temperatures ◽  
Ultrasound Assisted ◽  
High Concentrations ◽  
Static Extraction ◽  
Supercritical Carbon

Oleanolic acid (OA) and ursolic acid (UA) were extracted fromHedyotis diffusausing a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2) extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant) and UA (3.540 mg/g of dry plant) were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v) cosolvent (ethanol/water = 82/18, v/v) and SC–CO2flowing at 2.3 mL/min (STP). The extracted yields were then analyzed by high performance liquid chromatography (HPLC) to quantify the OA and UA. The present findings revealed thatH. diffusais a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA fromH. diffusaat high concentrations.

Study on the Crystallization Behavior of PAN Fibers during Hot-Drawing Process in Supercritical Carbon Dioxide Fluid with Different Strain

2020 ◽  
Vol 976 ◽  
pp. 84-89
Author(s):  
Meng Meng Qiao ◽  
Hai Juan Kong ◽  
Xiao Ma Ding ◽  
Zhi Feng Hu ◽  
Mu Huo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Carbon Fibers ◽  
Crystallization Behavior ◽  
Strength Analysis ◽  
Drawing Process ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

Hot-drawing of polyacrylonitrile (PAN) fibers is an important step in the production of carbon fibers. In this article, we investigated the effect of strain on the crystallization behavior and mechanical properties of PAN fibers treated in supercritical carbon dioxide (Sc-CO2) fluid. We mainly used the methods of X-ray diffraction (XRD), monofilament strength analysis and differential scanning calorimeter (DSC) to study the crystallization behavior, mechanical properties and thermal behavior of PAN fibers during hot-drawing process. The experimental results showed that the crystallinity and mechanical properties of PAN fibers both increased a lot under the action of strain during hot-drawing in Sc-CO2 fluid. This provides an important method for preparation of higher performance PAN precursor for PAN-based carbon fibers.

scholarly journals Extraction and Solubility Modeling of Anthocyanins Rich Extract from Hibiscus sabdariffa L. using Supercritical Carbon Dioxide

2021 ◽  
Vol 17 (6) ◽  
pp. 720-730
Author(s):  
Zuhaili Idham ◽  
Nicky Rahmana Putra ◽  
Hasmida Nasir ◽  
Lee Nian Yian ◽  
Nor Faadila Mohd Idrus ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Extraction Yield ◽  
Hibiscus Sabdariffa ◽  
Different Temperatures ◽  
Supercritical Carbon

This study aimed to evaluate the extraction yield, and anthocyanins content of Hibiscus sabdariffa L. calyces extract using different temperatures (T) at 50 - 70°C, pressure (P) at 8 - 12 MPa, and modifier ratio at 5 - 10%.  

Mechanical properties of microcellular and nanocellular silicone rubber foams obtained by supercritical carbon dioxide

2019 ◽  
Vol 51 (6) ◽  
pp. 559-568 ◽  
Author(s):  
Bin Xiang ◽  
Yalan Jia ◽  
Yajie Lei ◽  
Fengshun Zhang ◽  
Jiangping He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Silicone Rubber ◽  
Supercritical Carbon

scholarly journals Time-Dependence of Mechanical Property Alterations on Anthracite Coals Treated by Supercritical Carbon Dioxide

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Wei Li ◽  
Bin Pang ◽  
Er-lei Su ◽  
Quanlin Yang ◽  
Qingquan Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Time Dependence ◽  
Coal Mass ◽  
Stress Constraint ◽  
Physical Chemical ◽  
Anthracite Coal ◽  
Triaxial Compressive Strength ◽  
Supercritical Carbon

The injection of supercritical carbon dioxide (Sc-CO2) into coal seams remarkably changes the physical-chemical structures of coal mass and thereby improves coal mechanical properties. In this study, a series of unconfined and triaxial compressive strength tests were performed on anthracite coal samples under the pressure of 8 MPa at the temperature of 35°C for 24 h and 48 h, respectively. Besides, experiments with longer Sc-CO2 treatment time were carried out on coal mass without stress constraint to observe the damage mode of coal. The results show that Sc-CO2 treatment obviously alters time-dependent mechanical properties of anthracite coal. The coal samples treated with Sc-CO2 for 240 h and 960 h show different damage modes from limited fractures to a complicated fracture network. The time-dependence of the mechanical weakening model on Sc-CO2-treated coal was proposed to explain the link between CO2 flow and mechanical weakening effect by means of physical-chemical effects on time scales.

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