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Full-Text Articles in Physical Sciences and Mathematics

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert Nov 2015

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Vladimir Benin

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …


Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin Nov 2015

Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin

Vladimir Benin

The present report describes the preparation and characterization of several N-2-(trimethylsilyl)ethyl-N-nitrosocarbamates, designed as precursors to thermally unstable secondary N-nitrosocarbamate anions via fluoride-assisted cleavage. X-ray structural studies demonstrate that the core N-nitrosocarbamate moiety has a nearly planar geometry, with an s-E orientation at the N–N bond. DFT calculations (B3LYP/6-31+G(d)) reproduce accurately the structural features of the title compounds and detailed conformational analysis at the same level of theory addresses the long-standing issue of preferred geometries for three classes of related structures: N-nitrosocarbamates, N-nitrosoureas and N-nitrosoamides. Desilylation studies demonstrate that both the …


Ultra-Thin Microporous–Mesoporous Metal Oxide Films Prepared By Molecular Layer Deposition (Mld), X. Liang, Miao Yu, J. Li, Y.-B. Jiang, A. Weimer Jun 2015

Ultra-Thin Microporous–Mesoporous Metal Oxide Films Prepared By Molecular Layer Deposition (Mld), X. Liang, Miao Yu, J. Li, Y.-B. Jiang, A. Weimer

Miao Yu

No abstract provided.


Efficient Oxidation Of Arylmethylene Compounds Using Nano-Mno2, Baskar Nammalwar, Chelsea Fortenberry, Richard Bunce, Sathish Lageshetty, Kevin Ausman Dec 2012

Efficient Oxidation Of Arylmethylene Compounds Using Nano-Mno2, Baskar Nammalwar, Chelsea Fortenberry, Richard Bunce, Sathish Lageshetty, Kevin Ausman

Kevin D. Ausman

Nano-MnO2 has been developed as an efficient and mild reagent for the high-yield oxidation of arylmethylene compounds to the corresponding aldehydes and ketones as well as benzylic ethers to esters. The reagent is conveniently prepared and shows reactivity superior to synthetic (Attenburrow) MnO2 and commercial MnO2 under both microwave and conventional conditions. Typical reactions are performed using 25 wt % of nano-MnO2 relative to the substrate, and the reagent can be recycled up to six times without significant loss of activity. The observed conversions correlate well with surface-water content in the different MnO2 samples, as determined by thermogravimetric analysis.


The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed Busnaina Apr 2012

The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed Busnaina

Jin-Goo Park

The effect of frictional and adhesion forces attributed to slurry particles on the quality of copper surfaces was experimentally investigated during copper chemical mechanical planarization process. The highest frictional force of 9 Kgf and adhesion force of 5.83 nN were observed in a deionized water-based alumina slurry. On the other hand, the smallest frictional force of 4 Kgf and adhesion force of 0.38 nN were measured in an alumina slurry containing citric acid. However, frictional (6 Kgf) and adhesion (1 nN) forces of silica particles in the slurry were not significantly changed regardless of the addition of citric acid. These …


C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman Dec 2011

C60 Oxide As A Key Component Of Aqueous C60 Colloidal Suspensions, Befrika Murdianti, Joshua Damron, Martha Hilburn, Randall Maples, Rangika Hikkaduwa Koralege, Sathish Kuriyavar, Kevin Ausman

Kevin D. Ausman

Stable aqueous fullerene colloidal suspensions (nC60) are demonstrated to rely on the [6,6]-closed epoxide derivative of the fullerene (C60O) for stability. This derivative is present, though often unrecognized, in small quantities in nearly all C60 starting materials due to a reaction with air. The low-yield formation of nC60 from organic solvent solutions results from a preferential partitioning and thus enrichment of C60O in the colloidal particles. This partitioning is significantly retarded in the nC60 synthesis method that does not involve organic solvent solutions: long-term stirring in water. Instead, this method relies on trace levels of ozone in the ambient atmosphere …


Highly Fluorous Complexes Of Ruthenium And Osmium And Their Solubility In Supercritical Carbon Dioxide, Brad Berven, George Koutsantonis, Brian Skelton, Robert Trengove, Allan White Dec 2008

Highly Fluorous Complexes Of Ruthenium And Osmium And Their Solubility In Supercritical Carbon Dioxide, Brad Berven, George Koutsantonis, Brian Skelton, Robert Trengove, Allan White

Brad Berven

A series of ruthenium and osmium complexes containing highly fluorous diphosphine ligands FPPF = (F13C6C6H4-p)2P(CH2)2P(p-C6H4C6F13)2 (dfppe) and (F13C6C6H4-p)2P(CH2)3P(p-C6H4C6F13)2 (dfppp) has been prepared. The fluorous diphosphine ligands incorporate four C6F13 “fluoro-ponytails”, and these have been effective in solubilizing the complexes in supercritical carbon dioxide (scCO2). Precise solubility measurements in scCO2 were performed for some of the complexes. The new complexes [MX2(FPPF)2] and [MX(FPPF)(η-C5H5)], M = Ru, Os, X = Cl, Br, have been characterized by a number of spectroscopic techniques and their electrochemical properties measured, three of the ruthenium complexes also being characterized by single-crystal X-ray studies. The noncovalent interactions observed …


Highly Fluorous Bidentate Phosphines, Brad Berven, George Koutsantonis Dec 2007

Highly Fluorous Bidentate Phosphines, Brad Berven, George Koutsantonis

Brad Berven

The reaction of tetrachlorodiphosphines [Cl2P(CH2)nPCl2; n = 2-4] with fluorous aromatic precursors 4-bromo(perfluorohexyl)benzene and 4-(perfluorohexyl)phenol gave a series of fluorous-tagged diphosphines [(p-C6F13C6H4)2P(CH2)nP(C6H4C6F13-p)2; n = 2-4] and a new diphosphonite [(p-C6F13C6H4O)2P(CH2)3P(OC6H4C6F13-p)2]. The improved synthesis of 1,3-bis(dichlorophosphino)propane (dcpp), involved the facile chlorination of the corresponding primary phosphine with triphosgene. Fluorinated diimines RN=C(CH3)C(CH3)=NR, where R = p-C6H4C6F13 or p-C6H4C8F17 have also been prepared, and were found to be air-stable alternatives to the highly air-sensitive phosphorus-containing ligands. All compounds were characterised by a variety of techniques including NMR, IR, MS and microanalysis. The successful reduction of the phosphine-oxides [(p-C6F13C6H4)2P(O)(CH2)nP(O)(C6H4C6F13-p)2; n = 2,3] with phenylsilane …