Towards high-performance polypropylene and its random copolymer: Insight into toughening mechanism of supercritical carbon dioxide assisted annealing

2014 ◽  
Vol 87 ◽  
pp. 83-92 ◽  
Author(s):  
Chengzhen Geng ◽  
Guanghui Yang ◽  
Hongwei Bai ◽  
Yuhan Li ◽  
Qiang Fu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
High Performance ◽  
Random Copolymer ◽  
Toughening Mechanism ◽  
Insight Into ◽  
Supercritical Carbon

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.

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.

Mechanical Design and Validation Testing for a High-Performance Supercritical Carbon Dioxide Heat Exchanger

2017 ◽  
Author(s):  
Shaun D. Sullivan ◽  
Jason Farias ◽  
James Kesseli ◽  
James Nash
Keyword(s):  
Carbon Dioxide ◽  
Heat Exchanger ◽  
Supercritical Carbon Dioxide ◽  
Heat Exchangers ◽  
High Performance ◽  
Mechanical Design ◽  
Great Promise ◽  
Heat Rejection ◽  
Very High ◽  
Supercritical Carbon

Supercritical carbon dioxide (sCO2) Brayton cycles hold great promise as they can achieve high efficiencies — in excess of 50% — even at relatively moderate temperatures of 700–800 K. However, this high performance is contingent upon high-effectiveness recuperating and heat rejection heat exchangers within the cycle. A great deal of work has gone into development of these heat exchangers as they must operate not only at elevated temperatures and very high pressures (20–30 MPa), but they must also be compact, low-cost, and long-life components in order to fully leverage the benefits of the sCO2 power cycle. This paper discusses the mechanical design and qualification for a novel plate-fin compact heat exchanger designed for sCO2 cycle recuperators and waste heat rejection heat exchangers, as well as direct sCO2 solar absorber applications. The architecture may furthermore be extended to other very high pressure heat exchanger applications such as pipeline natural gas and transcritical cooling cycles. The basic heat exchanger construction is described, with attention given to those details which have a direct impact on the durability of the unit. Modeling and analysis of various mechanical failure modes — including burst strength, creep, and fatigue — are discussed. The design and construction of test sections, test rigs, and testing procedures are described, along with the test results that demonstrate that the tested design has an operating life well in excess of the 100,000 cycles/90,000 hour targets. Finally, the application of these findings to a set of design tools for future units is demonstrated.

A detailed insight into the preparation of nanocrystalline TiO2 powders in supercritical carbon dioxide

2017 ◽  
Vol 52 (21) ◽  
pp. 12635-12652 ◽  
Author(s):  
A. Hertz ◽  
M. Drobek ◽  
J.-C. Ruiz ◽  
F. Charton ◽  
S. Sarrade ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Nanocrystalline Tio2 ◽  
Insight Into ◽  
Supercritical Carbon

Lipase-catalyzed synthesis of aliphatic polyesters in supercritical carbon dioxide

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Tetsufumi Takamoto ◽  
Hiroshi Uyama ◽  
Shiro Kobayashi
Keyword(s):  
Carbon Dioxide ◽  
Molecular Weight ◽  
Supercritical Carbon Dioxide ◽  
Ring Opening ◽  
Monomer Concentration ◽  
Random Copolymer ◽  
Ring Opening Polymerization ◽  
Reaction Parameters ◽  
Aliphatic Polyesters ◽  
Supercritical Carbon

AbstractSynthesis of aliphatic polyesters has been examined using Candidaantarctica lipase in supercritical carbon dioxide (scCO2). The enzymatic ring-opening polymerization of ε-caprolactone (ε-CL) proceeded in scCO2 to give a polymer with molecular weight higher than 104. Effects of reaction parameters such as the monomer concentration, enzyme amount and pressure have been systematically investigated. Copolymerization of ε-CL with 12-docecanolide afforded the random copolymer. The enzymatic polycondensation of divinyl adipate and 1,4-butanediol also proceeded in scCO2 to produce the corresponding polyester.

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