Nucleation and growth in microcellar materials: supercritical CO2 as foaming agent

1996 ◽  
Vol 22 ◽  
pp. 93 ◽  
Author(s):  
S Goel
Keyword(s):  
Supercritical Co2 ◽  
Nucleation And Growth ◽  
Foaming Agent

Design of a Multifunctional Porous Coaxial Electrospun Mesh Using Polycaprolactone (PCL) and Poly Butylene Adipate-CO-Terephthalate (PBAT)

2016 ◽  
Author(s):  
Hussain R. Rizvi ◽  
Nandika D'Souza
Keyword(s):  
Tensile Testing ◽  
Supercritical Co2 ◽  
Fiber Diameter ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Mechanical Analysis ◽  
Delivery Vehicle ◽  
Foaming Agent ◽  
Sem Image ◽  
Coaxial Fibers

In this paper, we formulate a method to create a potential drug delivery vehicle and scaffold architecture of coaxial electrospun fibers. Having the capability to introduce porosity either in core or sheath of the fiber using supercritical CO2 as a foaming agent is utilized. Polycaprolactone (PCL) and Poly butylene adipate-co-terephthalate (PBAT) were used because of their biodegradable and biocompatible nature. Physical morphology of the porous coaxial fibers was studied using Scanning Electron Microscopy (SEM), Image J software was used to quantify the pore size and fiber diameter. Dynamic Mechanical Analysis (DMA) and Tensile Testing of the three-dimensional fibrous mesh was done to determine the mechanical properties of the porous structure. Differential Scanning Calorimeter (DSC) was used to study the thermal characteristics of the mesh.

The effect of supercritical CO2 as a reversible plasticizer and foaming agent on the hot stage extrusion of itraconazole with EC 20cps

2007 ◽  
Vol 40 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Geert Verreck ◽  
Annelies Decorte ◽  
Koen Heymans ◽  
Jef Adriaensen ◽  
Dehua Liu ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Foaming Agent

Preparation of porous poly(L-lactic acid)-co -(trimethylene-carbonate) structures using supercritical CO2 as antisolvent and as foaming agent

2016 ◽  
Vol 57 (9) ◽  
pp. 1005-1015 ◽  
Author(s):  
Apostolos Baklavaridis ◽  
Ioannis Tsivintzelis ◽  
Ioannis Zuburtikudis ◽  
Costas Panayiotou
Keyword(s):  
Lactic Acid ◽  
Supercritical Co2 ◽  
Trimethylene Carbonate ◽  
Foaming Agent ◽  
Porous Poly

Characterization of the porous structure of biodegradable scaffolds obtained with supercritical CO2 as foaming agent

2007 ◽  
Vol 15 (4) ◽  
pp. 397-403 ◽  
Author(s):  
Angélique Léonard ◽  
Cedric Calberg ◽  
Greet Kerckhofs ◽  
Martine Wevers ◽  
Robert Jérôme ◽  
...  
Keyword(s):  
Porous Structure ◽  
Supercritical Co2 ◽  
Foaming Agent ◽  
Biodegradable Scaffolds

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

1978 ◽  
Vol 36 (1) ◽  
pp. 454-455
Author(s):  
L.E. Murr ◽  
V. Annamalai
Keyword(s):  
Metal Surface ◽  
Copper Deposit ◽  
Nucleation And Growth ◽  
16Th Century ◽  
Electrochemical Reactions ◽  
Mine Shaft ◽  
De Re ◽  
Copper Precipitation ◽  
Electrochemical Nucleation ◽  
Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

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