Organic Curing Agents for Polysulfide Sealants. II. Additions of Thiols to Nitrile Oxides: Scope, Relative Reactivities and Application to the Cure of Polysulfide Sealants

1989 ◽  
Vol 42 (8) ◽  
pp. 1257 ◽  
Author(s):  
PJ Hanhela ◽  
DB Paul
Keyword(s):  
Ambient Temperature ◽  
Elevated Temperatures ◽  
Barium Oxide ◽  
Free Products ◽  
Ambient Temperatures ◽  
Nitrile Oxides ◽  
Curing Agents ◽  
In Situ Generation ◽  
Long Chain

Efficient addition between various nitrile oxides and both short (C2) and long chain (C16) alkyl thiols , aliphatic dithiols and aryl thiols occurred rapidly at ambient temperature with the formation of thiohydroximic acid derivatives. Competitive experiments with bis( nitrile oxides) showed that for terephthalonitrile oxide the second addition proceeded more readily than the first whereas with anthracene-9,l0-bis(carbonitrile oxide) elevated temperatures were needed to obtain the diadduct. Relative reactivities of a number of thiols with nitrile oxides were also determined spectroscopically . Reaction between prop-2-ene-1-thiol and p-nitrobenzonitrile oxide afforded products resulting from both cycloaddition and 1,3-addition with the latter predominating. The polysulfide prepolymer LP-2 was cured effectively at ambient temperatures by both terephthalonitrile oxide and 4,4'-sulfonylbisbenzonitrile dioxide at CNO to SH ratios of 1.5 and higher giving tack-free products within 0.5 h and 90% cure in under 4 h. For the less highly cross-linked LP-32-based sealants, curing was a little slower. Unreinforced sealants produced in this manner were firm elastomers with hardness of 35-40 (Rex A). The naphthalenebis (carbonitrile oxides) afforded softer products while anthracene-9,10- bis(carbonitrile oxide) was ineffective. One-part formulations involving in situ generation of nitrile oxide from hydroximoyl chlorides and barium hydroxide (formed by action of water vapour on barium oxide) were also produced.

In Situ Generation of Nitrile Oxides from NaCl–Oxone Oxidation of Various Aldoximes and Their 1,3-Dipolar Cycloaddition

2018 ◽  
Vol 21 (1) ◽  
pp. 315-319 ◽  
Author(s):  
Guodong Zhao ◽  
Lixin Liang ◽  
Chi Ho Ethan Wen ◽  
Rongbiao Tong
Keyword(s):  
Dipolar Cycloaddition ◽  
Nitrile Oxides ◽  
In Situ Generation

New method of in situ generation of nitrile oxides by MnO2 oxidation of aldoximes

1999 ◽  
Vol 40 (30) ◽  
pp. 5605-5608 ◽  
Author(s):  
Jarosław Kiegiel ◽  
Magdalena Popławska ◽  
Julita Jóźwik ◽  
Małgorzata Kosior ◽  
Janusz Jurczak
Keyword(s):  
New Method ◽  
Nitrile Oxides ◽  
In Situ Generation

scholarly journals Reaction-Based, Fluorescent Film Deposition from Dopamine and a Diamine-Tethered, Bis–Resorcinol Coupler

2019 ◽  
Vol 20 (18) ◽  
pp. 4532
Author(s):  
Maria Laura Alfieri ◽  
Mariagrazia Iacomino ◽  
Alessandra Napolitano ◽  
Marco d’Ischia
Keyword(s):  
Spectral Analysis ◽  
Film Deposition ◽  
Emission Properties ◽  
Carbonate Buffer ◽  
Film Forming ◽  
Fluorescent Materials ◽  
In Situ Generation ◽  
Long Chain

The reaction-based deposition on various surfaces of an all-organic fluorescent coating is reported here, involving autoxidation of 2 mM dopamine in carbonate buffer at pH 9.0, in the presence of a 1 mM diamine–resorcinol coupler (Bis–Res) prepared from 2,4-dihydroxybenzaldehyde and hexamethylenediamine (HMDA). Spectral analysis of the films coupled with an LC-MS investigation of the yellow fluorescent mixture was compatible with the formation and deposition of HMDA-linked methanobenzofuroazocinone fluorophores. Both the emission properties and hydrophobicity of the film were abated in a reversible manner following exposure to acid vapors. These results provide an entry to efficient and practical fluorescent coating methodologies based on in situ generation and the deposition of wet adhesive, as well as fluorescent materials combining a strongly emitting fluorophore with the film-forming properties of long chain diamines.

Microstructure of Directionally Solidified Ni-Ni3Si Hypoeutectic In Situ Composite

2011 ◽  
Vol 284-286 ◽  
pp. 230-233 ◽  
Author(s):  
Chun Juan Cui ◽  
You Ping Ma ◽  
Lei Yang ◽  
Ke Yong Zhai
Keyword(s):  
Directional Solidification ◽  
Elevated Temperatures ◽  
Solidification Rate ◽  
High Strength ◽  
Eutectic Structure ◽  
Ductile Phase ◽  
In Situ Composites ◽  
Ambient Temperatures ◽  
Sulfuric Acid Solutions

Ni3Si compound is one of the excellent high temperature structural materials, because it possesses the attributes of high melting point, high strength, low density, excellent oxidation resistance at elevated temperatures, and magnificent corrosion resistance in acid environments, particularly sulfuric acid solutions, while the application of this compound is limited due to poor ductility at ambient temperatures and lack of fabricability at high temperatures. The incorporation of a ductile phase into the intermetallic materials has become an attractive means to modify the ductility. In this paper Ni-Ni3Si hypoeutectic in situ composites are obtained by Bridgman directional solidification technology. Microstructure of the Ni- Ni3Si hypoeutectic in situ composites are regular lamellar eutectic structure at the lower solidification rates, whereas eutectic cells or dendrites can be found with the increase of the solidification rate, due to the increase of the composition undercooling. Moreover, the directional solidification mechanism was investigated as well.

scholarly journals Effect of Elevated Ambient Temperature on Simulator-Derived Oscillometric Blood Pressure Measurement

2020 ◽  
Author(s):  
Jennifer S Ringrose ◽  
Michael D Kennedy ◽  
Jalisa Kassam ◽  
Omar Mouhammed ◽  
Sangita Sridar ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Elevated Temperature ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Blood Pressure Measurement ◽  
Ambient Temperatures ◽  
Oscillometric Blood Pressure Measurement ◽  
Increasing Temperature ◽  
Relative Differences

Abstract BACKGROUND Oscillometric blood pressure (BP) devices are typically labeled for use up to 40 °C. Many geographic regions have ambient temperatures exceeding 40 °C. We assessed the effect of increased ambient temperature (40–55 °C) on simulator-derived oscillometric BP measurement. METHODS Three Omron BP769CAN devices, 3 A&D Medical UA-651BLE devices, and accompanying cuffs were used. A custom heat chamber heated each device to the specified temperature. A noninvasive BP simulator was used to take 3 measurements with each device at differing temperatures (22, 40, 45, 50, and 55 °C) and BP thresholds: 80/50, 100/60, 120/80, 140/90, 160/110, and 180/130 mm Hg. Using each device as its own control (22 °C), we determined the relative differences in mean BP for each device at each temperature and BP setting, assessed graphical trends with increasing temperature, and examined variability. RESULTS Graphical trends of mean simulator-subtracted BP differences from room temperature showed no discernable pattern, with differences clustered around zero. Overall mean difference in BP (combined elevated temperatures minus room temperature) was −0.8 ± 2.1 (systolic ± SD)/1.2 ± 3.5 (diastolic ± SD) mm Hg for the A&D device and 0.2 ± 0.4 (systolic ± SD)/−0.1 ± 0.1 (diastolic ± SD) mm Hg for the Omron. All individual elevated temperature differences (elevated temperature minus room temperature) except A&D diastolic BP at 50 °C were within 5 mm Hg. CONCLUSIONS In this simulator-based study assessing within-device differences, higher ambient temperatures resulted in oscillometric BP measurements that were comparable to those performed at room temperature.

ChemInform Abstract: New Method for in situ Generation of Nitrile Oxides by MnO2 Oxidation of Aldoximes.

ChemInform ◽  
2010 ◽  
Vol 30 (44) ◽  
pp. no-no
Author(s):  
Jaroslaw Kiegiel ◽  
Magdalena Poplawska ◽  
Julita Jozwik ◽  
Malgorzata Kosior ◽  
Janusz Jurczak
Keyword(s):  
New Method ◽  
Nitrile Oxides ◽  
In Situ Generation

In situ generation of nitrile oxides from copper carbene and tert-butyl nitrite: synthesis of fully substituted isoxazoles

2018 ◽  
Vol 16 (25) ◽  
pp. 4683-4687 ◽  
Author(s):  
Rongxiang Chen ◽  
Abosede Adejoke Ogunlana ◽  
Shangwen Fang ◽  
Wenhao Long ◽  
Hongmei Sun ◽  
...  
Keyword(s):  
Cycloaddition Reaction ◽  
Nitrile Oxides ◽  
Tert Butyl ◽  
Keto Esters ◽  
In Situ Generation

Herein, a novel [3 + 2] cycloaddition reaction of β-keto esters with nitrile oxides, which were generated in situ from copper carbene and tert-butyl nitrite, was developed effectively to give fully substituted isoxazoles.

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

The threshold energy for atom displacement in fcc metals

1990 ◽  
Vol 48 (4) ◽  
pp. 530-531
Author(s):  
Wilfried Sigle ◽  
Matthias Hohenstein ◽  
Alfred Seeger
Keyword(s):  
Growth Rate ◽  
Elevated Temperatures ◽  
Threshold Energy ◽  
Dislocation Loops ◽  
Absolute Minimum ◽  
Voltage Electron ◽  
Atom Displacement ◽  
Electron Microscopes ◽  
Fcc Metal

Prolonged electron irradiation of metals at elevated temperatures usually leads to the formation of large interstitial-type dislocation loops. The growth rate of the loops is proportional to the total cross-section for atom displacement,which is implicitly connected with the threshold energy for atom displacement, Ed . Thus, by measuring the growth rate as a function of the electron energy and the orientation of the specimen with respect to the electron beam, the anisotropy of Ed can be determined rather precisely. We have performed such experiments in situ in high-voltage electron microscopes on Ag and Au at 473K as a function of the orientation and on Au as a function of temperature at several fixed orientations.Whereas in Ag minima of Ed are found close to <100>,<110>, and <210> (13-18eV), (Fig.1) atom displacement in Au requires least energy along <100>(15-19eV) (Fig.2). Au is thus the first fcc metal in which the absolute minimum of the threshold energy has been established not to lie in or close to the <110> direction.

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