Thermally-induced polymerization of 1,4s-diphenyls-1,2,3s-butatriene affords poly(1,4s-diphenyls- 2s-butynes-1,4s-diyl) as a soluble high molecular weight material. Structure is characterized by 13C and vibrational sp...
Thermally-induced polymerization of 1,4s-diphenyls-1,2,3s-butatriene affords poly(1,4s-diphenyls- 2s-butynes-1,4s-diyl) as a soluble high molecular weight material. Structure is characterized by 13C and vibrational spectroscopy. When treated with base, this material rearranges to a soluble red poly(acetylene) with a unique substitution pattern.
The cleaning effectiveness of flowing hydrogen to remove oxygen (adsorbed and metal oxide) and carbon (elemental, carbides and carbon-hydrogen complex) from the surface of nanostructured alpha-iron and M50 type steel ...
The cleaning effectiveness of flowing hydrogen to remove oxygen (adsorbed and metal oxide) and carbon (elemental, carbides and carbon-hydrogen complex) from the surface of nanostructured alpha-iron and M50 type steel (Fe-Cr-Mo-V-C) alloy powders was investigated. The hydrogen treated powders and consolidated material were examined by bulk chemical analysis and metallographic examination. The trends in the cleaning effectiveness compared favorably with predictions from Richardson and Jeffies plots of metal-metal oxide equilibria.
The evaluation of contaminant concentrations in ground water and soil is an essential aspect of most hazardous waste remedial investigations. This paper describes methods applied toward obtaining, preserving, and anal...
The evaluation of contaminant concentrations in ground water and soil is an essential aspect of most hazardous waste remedial investigations. This paper describes methods applied toward obtaining, preserving, and analyzing subsurface samples for the determination of VOC concentrations in the saturated region of an unconfined coastal plain aquifer at Dover Air Force Base (DAFB), Delaware. The described protocol involved headspace-free subsampling of cores, field preservation of subsamples in methanol, and overnight extraction of the VOCs at elevated temperature (70 degrees C). Methanol-extracted compounds were subsequently transferred to hexane and analyzed by gas chromatography. The method was found to achieve quantitative extraction from the aquifer sands in a single step, although extraction from fine-grained and more strongly sorbing aquitard samples required multiple methanol extractions to achieve comparable recovery. An extensive set of DAFB results is presented as an indication of how these methods can be applied toward characterizing field-scale contamination with a high degree of resolution and accuracy. These data have enabled a quantitative estimate of the contaminant distribution at this site and offer valuable insight into processes of contaminant migration into the underlying aquitard. In these regards, the methods used are believed to have provided much more accurate results than could have been obtained using more commonly applied techniques.
The reactivity of a novel series of mono-, di-, and multifunctional monomers bearing the epoxynorbornane group in photoinduced cationic polymerization was determined using Fourier transform real-time infrared spectros...
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The reactivity of a novel series of mono-, di-, and multifunctional monomers bearing the epoxynorbornane group in photoinduced cationic polymerization was determined using Fourier transform real-time infrared spectroscopy and differential scanning photocalorimetry. Comparisons were made between the monomers of this investigation containing the epoxynorbornane group with monomers of similar structure bearing epoxycyclohexane groups. Although the cationic polymerizations of the epoxynorborane functional monomers are rapid they, are slower than the aforementioned epoxycyclohexane analogues. This was attributed mainly to steric hindrance effects.
The synthesis of a series of mono-, di-, and multifunctional monomers bearing the epoxynorbornane group has been carried out. Key to their preparation is the chemoselective epoxidation of 5-vinyl-2-norbornene, which a...
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The synthesis of a series of mono-, di-, and multifunctional monomers bearing the epoxynorbornane group has been carried out. Key to their preparation is the chemoselective epoxidation of 5-vinyl-2-norbornene, which affords the 5-vinyl-exo-2,3-norbornane epoxide in high yields. Monomers were prepared using this substrate and carrying out hydrosilations to make mono-, di-, tri-, and tetrafunctional epoxides. The esterification and etherification of 5-norbornene-2-methanol with succinic acid and 1,4-butanediol gives the corresponding bisnorbornene compounds, which were epoxidized to give diepoxynorbornane monomers containing ester and ether linkages. All monomers were fully characterized by means of IR and H-1 and C-13 NMR spectroscopy and by elemental analysis.
This paper demonstrates the generation of DSC thermograms from TREF chromatograms. The reverse is clearly possible, and shows that compositional distribution information is obtainable from DSC using solution crystalli...
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This paper demonstrates the generation of DSC thermograms from TREF chromatograms. The reverse is clearly possible, and shows that compositional distribution information is obtainable from DSC using solution crystallized material. However, TREF is essential, at least initially, in providing fractions for calibration curves.
A review of the current trends in microlithography is presented including the science and chemistry ofthis technology. The microelectronics technology has progressed with at an astounding rate during the pastseveral d...
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The phase behavior of blends of zinc sulfonated polystyrene (ZnSPS) and bisphenol-A polycarbonate (PC) was studied as a function of the sulfonation level and the molecular weight of the ZnSPS ionomer. The system exhib...
The phase behavior of blends of zinc sulfonated polystyrene (ZnSPS) and bisphenol-A polycarbonate (PC) was studied as a function of the sulfonation level and the molecular weight of the ZnSPS ionomer. The system exhibits upper critical solution temperature (UCST) behavior. The cloud point temperatures increased with increasing ZnSPS molecular weight and decreased with increasing sulfonation level. No strong interactions between ZnSPS and PC were detected by FTIR. The composition dependence of the glass transition temperatures of the miscible blends exhibited negative deviation from linear additi vity, which is consistent with no or weak interactions between ZnSPS and PC. Miscibility is believed to arise from strong repulsive interactions between the charged and uncharged species on the ionomer chain.
The properties of ultralow-density polyethylenes (ULDPE) have been studied using temperature rising elution fractionation (TREF) as both an analytical and preparative process. TREF was employed to determine the short ...
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The properties of ultralow-density polyethylenes (ULDPE) have been studied using temperature rising elution fractionation (TREF) as both an analytical and preparative process. TREF was employed to determine the short chain branch distribution and to fractionate the polymer into fractions that enabled further properties studies, including carbon-13 nuclear magnetic resonance, differential scanning calorimetry, dynamic mechanical thermal analysis, density gradient studies, gel permeation chromatography, analytical TREF, and some simple tensile tests. The results of these studies are reported here.
It is of critical importance to safety in the nuclear power industry to estimate the lifetime of polymeric materials in an environment featuring elevated temperatures and radiation. To this end, the authors are examin...
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It is of critical importance to safety in the nuclear power industry to estimate the lifetime of polymeric materials in an environment featuring elevated temperatures and radiation. To this end, the authors are examining the aging of polymeric materials, in cables and other components in nuclear reactor containments by comparing aging processes for a variety of materials under natural conditions with those under accelerated laboratory conditions typical of those used in qualification. The physical property data derived from naturally and artificially aged specimens are compared using three methods: (1) a traditional method; (2) activation energy from natural data alone; and (3) an internal standards method. All three methods work with the properties of the material in its aged, but usable state, and not with a failure time of the material.
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