| Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 19. Synthesis and Characterization of Poly(2-(4-Biphenyloxy) ethyl Vinyl Etherby |
27 MAR 92 |
22 pages |
| Authors:
Virgil Percec; Myongsoo Lee; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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 | The synthesis and living cationic polymerization of 2-(4-biphenyloxy) ethyl vinyl ether (BEVE) are described. Polymers with degrees of polymerization from 3.8 to 22.1 and narrow molecular weight distribution were synthesized and characterized by differential scanning calorometry (DSC) and thermal optical polarized microscopy. When determined from their first DSC heating scans POLY(BEVE)s exhibit only a crystalline phase over the entire range of molecular weights. When determined from the second and first ... |
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| Molecular Engineering of Side Chain Liquid Crystalline Polymers |
27 MAR 92 |
24 pages |
| Authors:
Virgil Percec; Dimitris Tomazos; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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| This chapter discusses the molecular engineering of side chain liquid crystalline polymers mainly by living polymerization reactions. According to thermodynamic schemes, the polymer effect through its molecular weight and backbone flexibility can provide an overall change of entropy of the system. Consequently it can transform virtual mesophases into monotropic and enantiotropic mesophases. The control of molecular weight provided by living cationic polymerization of mesogenic vinyl ethers can be used successfully ... |
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| Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 20. Synthesis and Characterization of Binary Copolymers of 11- (4-Cyano-4'-biphenyl) Oxy)undecanyl Vinyl Ether with n-Butyl Vinyl Ether and of 2-(4-Cyano-4'biphenyl)oxy)ethyl V |
27 MAR 92 |
22 pages |
| Authors:
Virgil Percec; Myongsoo Lee; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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| Copolymerization represents the simplest synthetic technique which can be used to tailor make phase transitions of both main chain and side chain liquid crystalline polymers. Indeed, copolymerization was frequently employed to manipulate the phase transitions of side chain liquid crystalline polymers. However, most of the results reported in the literature can be considered only in a qualitative way, since there are only very few cases in which information about both ... |
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| Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 22. Synthesis and Characterization of Binary Copolymers |
27 MAR 92 |
42 pages |
| Authors:
Virgil Percec; Myongsoo Lee; Qiang Zheng; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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| The synthesis and characterization of poly(11-(4-cyano-4'-biphenyl) oxy)undecanyl vinyl ether-co-(2S,3S)-(+)-2-chloro-3-methylpentyl 4'-(8- vinyloxyoctyloxy)biphenyl-4-carboxylate)X/Y (poly(6-11)-co-(15-8)X/Y) (where X/Y represents the molar ratio of the two structural units) and poly(2S,3S)-(+)-2- chloro-3-methylpentyl 4'-(8-vinyloxyoctyloxy)biphenyl-4-carboxylate-co-3-((4- cyano-4'-biphenyl)oxy)propyl vinyl ether)X/Y (poly(15-8)-co-(6-3))X/Y) with degree of polymerization of about 20 and molecular weight distribution of about 1.1 are described. The mesomorphic behavior of all copolymers determined from both first, second and subsequent differential scanning calorimetric (DSC) scans was discussed as a function ... |
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| Reactive Skin Decontaminant Reactivity Studies: The Effect of O-Acetyl 2,3-Butanedione Monooxime on the Stability of 2,3-butanedione Monooximate |
MAR 92 |
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| Authors:
R. G. Clewley; J. G. Purdon; C. L. Chenier; DEFENCE RESEARCH ESTABLISHMENT SUFFIELD RALSTON (ALBERTA)
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 | The reaction of acetic anhydride with 2,3-butanedione monooximate, to generate in situ O-acetyl 2,3-butanedione monooxime, has been examined in four solvents. In water, the initially formed O-acetyl oxime undergoes a general-base catalysed Beckmann rearrangement; if present in excess, one equivalent of oximate is consumed by every equivalent of acetic anhydride. In acetonitrile, O- acetyl 2,3-butanedione monooxime catalyses the dispropotionation of 2,3- butanedione monooximate. In RSD formulations employing polyethylene glycol monomethyl ... |
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| Pregrooving on Glass Disks by the Sol-Gel Method. Part 2. Effects of the Addition of Organic Polymers on the Formation of Glass Films in the SiO2-TiO2 System, |
MAR 1992 |
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| Authors:
Atsunori Matsuda; Yoshihiro Matsuno; Shigeyuki Kataoka; Shinya Katayama; Toshio Tsuno; OSAKA PREFECTURE UNIV (JAPAN) DEPT OF APPLIED CHEMISTRY
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| The effects of the addition of polyethylene glycol(PEG) on the formation of gel-derived glass films in the SiO2-TiO2 system were studied, aimed at their application to the optical memory disks. The viscosity of the as-prepared sols increased almost linearly with increasing PEG content. The increase in viscosity of the sols during the storage was retarded with decreasing molecular weight of PEG added and with increasing amount of PEG added. The ... |
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| Pregrooving on Glass Disks by the Sol-Gel Method. Part 1. Formation and Evaluation of Pregrooved Glass Disks, |
MAR 1992 |
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| Authors:
Atsunorl Matsuda; Yoshihiro Matsuno; Shigeyuki Kataoka; Shinya Katayama; Toshio Tsuno; OSAKA PREFECTURE UNIV (JAPAN) DEPT OF APPLIED CHEMISTRY
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| Pregrooved glass disks were prepared by the application of the sol-gel coating technique; the soda-lime-silica glass disks were coated with polyethylene glycol(PEG)-containing SiO2-TiO2 gel films, in which fine patterns were formed by pressing a stamper. The refractive index of the pregrooved layer was matched with that of the glass disks by adjusting the TiO2 content. When the weight ratio of PEG with the average molecular weight of 600 to SiO2-TiO2) ... |
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| The Preparation of Tailored Length Thiophene Benzobisthiazole Oligomers with Solubilizing Decyloxy Pendants for Third Order Nonlinear Optical Property Correlations |
FEB 92 |
23 pages |
| Authors:
Marilyn R. Unroe; Bruce A. Reinhardt; WRIGHT LAB WRIGHT-PATTERSON AFB OH
|
| In an effort to better understand the relationship between molecular weight and third-order nonlinear optical (NLO) activity for condensation polymers, a series of thiophene containing benzobisthiazoles were synthesized via a trimethylsilylpolyphosphate (PPSE) catalysed condensation of a bis-o- aminothiophenol monomer and a didecyloxythiophene dicarboxylic acid. The physical and chemical characterization of these oligomers, including molecular weight determinations, are summarized. The enhancement of the bulk susceptibility and second molecular hyperpolarizability are demonstrated ... |
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| Chemistry of Organoindium Hydrides. The Synthesis, Characterization and Crystal Structure of K(H(In(CH2CMe3)3)2) |
21 JAN 92 |
26 pages |
| Authors:
O. T. Beachley Jr.; Sun-Hua Chao; Melvyn R. Churchill; Ronald F. See; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Two new organoindium hydrides have been prepared and fully characterized according to their physical properties, partial elemental analyses, molecular weight studies and IR and 1H and 13C NMR spectral studies. The unique hydrogen atoms bonded to indium in the two compounds provide characteristic infrared bands and 1H NMR resonances which have been identified by comparative studies with the corresponding deuterium derivatives. Compounds which contain indium hydrogen bonds are difficult to ... |
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| Macromolecular Flows |
09 JAN 92 |
16 pages |
| Authors:
CALIFORNIA UNIV SANTA BARBARA DEPT OF CHEMICAL AND NUCLEAR ENGINEERING
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| One of the unresolved problems of fluid mechanics with the greatest potential for important applications is turbulent drag reduction induced via the addition of additives, usually minute quantities of very high molecular weight polymer. This problem is unresolved in the sense that the basic mechanism remains a matter of controversy, and thus, the ability to optimize the process is limited. In part, this is because of the complexity of the ... |
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| Synthesis, Characterization, and Polymerization of New Ferrocene- Fluorene Complexes. A Novel High-Molecular Weight Conjugated Polymer with Pendant Ferrocene Groups |
92 |
30 pages |
| Authors:
Michael E. Wright; Brooks B. Cochran; UTAH STATE UNIV LOGAN DEPT OF CHEMISTRY AND BIOCHEMISTRY
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| Ferrocenecarboxaldehyde was successfully condensed with fluorene derivatives to afford a series of new complexes, (eta5-C5H5) Fe(eta5-C5H4CH=(9- fluorenyl)) where fluorenyl = 1A, 2-bromo: 2a, 2,7-dibromo; 3, 2-nitro. The ferrocene-fluorenyl derivatives la and 2a were converted to the monocarboxaldehyde, tributylstannyl, bis(carboxaldehyde), and bis(tributylstannyl) complexes (lb, lc, 2b, and 2c, respectively). Complexes lb and 2b were characterized by single-crystal x-ray molecular structures. The fluorenyl ring systems were tilted out of the eta5-C5H4 plane ... |
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| Synthesis of Oligoimides and Oligoimide Anion Radicals |
92 |
11 pages |
| Authors:
Larry L. Miller; MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMISTRY
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| Key to the results described in parts B-D are compounds based on naphthalene dianhydride (A) and dimethoxybenzidine (B). It was demonstrated that AB type oligoimides with lengths up to 80 A (8nm) (BABABAB) could be synthesized as single molecular weight, pure and usually soluble compounds. Although rotation about the single bonds along the chain is possible, the chains cannot fold. These oligomers constitute the longest, single molecular weight rigid rods ... |
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| High Strain Impact Ignition of RDX with Ethylene-Vinyl Acetate (EVA) copolymers |
92 |
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| Authors:
Ian J. Dagley; Sook Y. Ho; Luciana Montelli; Craig N. Louey; MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA)
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| The effects of vinyl acetate content and molecular weight of ethylene-vinyl acetate (EVA) copolymers on the high strain rate impact ignition sensitiveness of RDX/EVA (95:5) physical mixtures, explosive molding powders, and compacted charges were evaluated. In a drop-weight impact test on physical mixtures and molding powders, the high strain rate mechanical properties and thermal properties of the polymers, and the way the polymer is distributed, affect impact sensitiveness. Localized viscous ... |
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| Feasibility Study for the USAF, Relating to Provision of Samples of New Perfluoropolyethers, for Testing as Novel Lubricants |
92 |
5 pages |
| Authors:
R. D. Chambers; M. P. Greenhall; DURHAM UNIV (UNITED KINGDOM)
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| Perfluorinated polyethers are an important component of the long-term strategy of the USAF, as high-temperature lubricants. Current, commercially- available materials are exemplified by the 'KRYTOX' (1) (DuPont), 'FOMBLIN' (2) (Montefluos), and 'DEMNUM' (3) (Daikin) fluids. All of these products involve a polymerisation, of a fluorinated precursor, which can be difficult to control. In particular, it is difficult to obtain high molecular weight material. |
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| Organic NLO Polymers. Linear and Accordian Main-Chain NLO Polymers Prepared by a Knoevenagel Polycondensation |
13 DEC 91 |
4 pages |
| Authors:
Michael E. Wright; Sanjoy Mullick; UTAH STATE UNIV LOGAN DEPT OF CHEMISTRY AND BIOCHEMISTRY
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| A new main-chain NLO polymer was prepared by transesterification and the Knoevenagel polycondensation. The latter polymer product was obtained as a higher molecular weight polymer with good solubility in organic solvents. New bis(arylcarboxaldehyde) monomers were prepared and copolymerized with bis(cyanoacetate) monomers to afford accordion main-chain NLO polymers. The polymers were characterized by spectroscopic and analytical data, thermal analysis, and GPC. |
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| Organometallic NLO Polymers. Accordian Main-Chain NLO Polymers of Ferrocene |
13 DEC 91 |
4 pages |
| Authors:
Michael E. Wright; Matthew S. Sigman; UTAH STATE UNIV LOGAN DEPT OF CHEMISTRY AND BIOCHEMISTRY
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| Bis(ferrocene) NLO-phore monomers were prepared. The new bis(ferrocene) monomer was successfully copolymerized with bis(cyanoacetate) comonomers using a Knoevenagel polycondensation technique. The polymers were characterized by spectroscopic, thermal analysis, and GPC data. The polymers had average molecular weights in the range of 5000 to 25,000. In the previous paper we presented the synthesis of linear organometallic main-chain NLO polymers. Our research has continued to focus on ferrocene based NLO polymers because ... |
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| Progress on Polymer Degradation by Photoelectron Transfer |
DEC 91 |
15 pages |
| Authors:
John W. Cullen; Stephen J. Weininger; David E. Remy; ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
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| 1,5-Bis(3-hydroxypropoxy)-9,10-dimethoxyanthracene has been prepared and incorporated into poly (2-butynediyl oxalate). The photolysis results of the copolymer are described. Progress toward the preparation of 2-(4- carboxyphthalimoyl)-9,10- dimethoxyanthracene from 2-amino-9, 10-anthraquinone and mellitic anhydride is described is described. Synthetic intermediates have been characterized by ultraviolet visible, infrared and proton nuclear magnetic resonance spectroscopy. For some time this laboratory has been interested in energy absorptive materials, specifically polymers which could decompose cleanly to ... |
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| A Priori Calculations of Thermodynamic Functions |
DEC 91 |
223 pages |
| Authors:
Floyd R. Cordell; TEXAS UNIV AT AUSTIN
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| A method for calculating a priori thermodynamic functions (specific heat, entropy, free energy, and enthalpy) from a combination of single determinant ab initio calculations employing the 4-21NO basis and experimental data is developed and validated. An estimate of the re geometry is determined by empirically correcting the optimized 4-21NO ab initio geometry with formulae derived from carefully selected experimental re rs and rg geometries for errors caused by basis set ... |
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| Carboxyalkylated Hemoglobin as a Potential Blood Substitute |
19 NOV 91 |
25 pages |
| Authors:
James M. Manning; ROCKEFELLER INST NEW YORK
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| The major focus has been on the preparation and full characterization of a new hemoglobin crosslinker - 2,5-diisothiocyanatobenzene sulfonic acid. Collaborative studies with investigators at the Letterman Army Institute of Research indicated that carboxymethylated hemoglobin was cleared from the circulation of rats with a half time of 42 minutes. The pseudo-first order plot indicates that a homogeneous population of molecules was present. In addition, there was no adverse pathological findings. ... |
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| Annual Report for Contract N00014-91-J-1442 (University of Chicago) |
06 NOV 91 |
3 pages |
| Authors:
Karl F. Freed; CHICAGO UNIV IL JAMES FRANCK INST
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| Our research has resulted in one paper which is in press as follows: Role of Monomer Structure and Compressibility on the Properties of Multicomponent Polymer Blends and Solutions: IV. High Molecular Weights, Temperature Dependences, and Phase Diagrams of Binary Polymer Blends. We have applied the compressible lattice cluster theory of structured polymer blends to studying how the effective interaction parameter varies with composition, monomer structure, microscopic interactions, and temperature. We ... |
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| Molecular Engineering of Liquid Crystal Polymers by Living Polymerization. 17. Characterization of Poly(10-((4-Cyano-4'-Biphenyl)oxy) decanyl Vinyl Ether)s by 1-D and 2-D H-NMR Spectroscopy |
30 OCT 91 |
14 pages |
| Authors:
Virgil Percec; Myongsoo Lee; Peter L. Rinaldi; Vincent E. Litman; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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| Since the first examples of mesogenic vinyl ethers and liquid crystalline poly(vinyl ether)s were reported from our laboratory, several research groups became actively engaged in the synthesis of liquid crystalline poly(vinyl ether)s mainly because they can be polymerized by living cationic mechanism. So far, we have elucidated the influence of molecular weight on the phase transitions of poly(omega-((4-cyano-4'-biphenyl)oxy)alkyl vinyl ether)s with alkyl groups from ethyl to undecanyl. Binary copolymerization experiments ... |
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| Electronic and Ionic Transport in Processable Conducting Polymers. Symmetry Effects on the Physical and Electrically Conducting, Substituted Poly(di-2-thienylphenylenes) |
21 OCT 91 |
55 pages |
| Authors:
Jose P. Ruiz; Jayesh R. Dharia; John R. Reynolds; Leonard J. Buckley; TEXAS UNIV AT AUSTIN DEPT OF CHEMISTRY
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| Effect of symmetry on the physical and electronic properties of a series of conjugated polymers composed of di(2 thienyl) 2,5 disubstitutedphenylene repeat units, symmetrically and asymmetrically substituted with methoxy, heptoxy, dodecyloxy, hexadecyloxy, eicosinoxy and hexyl groups were studied. Polymers were prepared via an oxidative polymerization using ferric chloride and isolated after dedopping with ammonium hydroxide. Neutral polymers, soluble in common organic solvents including chloroform, methylene chloride and tetrahydrofuran, are predominantly ... |
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| Viscometry Constants for 1,4 Polybutadiene in Tetralin at 135C |
21 OCT 91 |
10 pages |
| Authors:
M. M. Nir; R. E. Cohen; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
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| During the course of a research program on blends of crystallizable polybutadiene (PBD) isomers, we needed to determine the molecular weight of a trans 1,4 polybutadiene sample. Gel Permeation Chromatography (GPC) of the trans 1,4 PBD in 140 C tetralin was unsuccessful due to extensive polymer degradation during testing. Therefore, we obtained Mark-Houwink constants for a series of 1, 4 PBD (mixed cis/trans) standards of known molecular weight and low ... |
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| Isolation and Characterization of Proteins from Campylobacter and Other Enteric Pathogens |
30 SEP 91 |
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| Authors:
T. J. Raybould; HAWAII BIOTECHNOLOGY GROUP INC AIEA
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| The Technical Objectives were to Develop in vitro bactericidal assay system and use to evaluate immune mouse sera from the Infectious Diseases Department, Naval Medical Research Institute (NMRI) Characterize denatured and non denatured proteins of Campylobacter coli and C. jejuni; Identify what molecular weight bands in PAGE/WB are responsible for precipitation lines and peaks in ODID and 2D-IE; Immunize rabbits and mice with 2D-IE precipitation peaks (or ODID precipitation lines) ... |
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| The Genetic Basis of Specificity in Dinoflagellate-Invertebrate Symbiosis |
30 SEP 91 |
4 pages |
| Authors:
Robert K. Trench; CALIFORNIA UNIV SANTA BARBARA MARINE SCIENCE INST
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| The prime goals of this award were: (1) to study the composition of the cell walls of symbiotic dinoflagellates, (2) analyse the chemical composition of the glycoproteins exuded by symbiotic dinoflagellates and (3) sequence the SSU rRNA gene from the symbiotic dinoflagellate Symbiodinium pilosum and assess its phylogenetic position relative to other protists. All three of these goals have been accomplished, and manuscripts or published papers describing the observations are ... |
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| Development of Safe, Effective Vaccines for Dengue Virus Disease by Recombinant Baculovirus. Subtitle: Development of Safe, Effective Vaccines for Dengue Disease Utilizing Viral Envelope and NSI Glycoproteins Expressed by Recombinant Baculovirus |
16 SEP 91 |
21 pages |
| Authors:
Ching-Juh Lai; NATIONAL INSTITUTES OF HEALTH BETHESDA MD
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| During the initial phase of this study we have completed construction of recombinant baculoviruses that separately express full-length E or NS1 glycoprotein of dengue type 2 and type 4 viruses. Radio-immunoprecipitation was performed to analyze the dengue product in the lysate of recombinant virus infected cells. The results showed that insect cells infected with recombinant b (DEN 4, 100%E) produced a protein with molecular weight of 55-60 kilodalton (Kd) as ... |
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| Fast Atom Bombardment Mass Spectrometric Characterization of Poly(O- Toluidine) |
20 AUG 91 |
26 pages |
| Authors:
K. Balasaunmugam; K. G. Owens; K. F. Hsueh; P. Hoontrakul; M. A. Olsen; PENNSYLVANIA UNIV PHILADELPHIA DEPT OF CHEMISTRY
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| Fast atom bombardment (FAB) mass spectrometry has been used to analyze chemically prepared and fractionated poly(O-toluidine) of low molecular weight (m/z < 5800) to evaluate its potential for the characterization of polymers of similar structure. In the lower mass range (m/z 400-1800) ionic species detected are separated by the mass of a toluidine monomer unit (m/z = 105). An interesting feature of the mass spectra is the observation that the ... |
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| Military Laser Systems - A Costly Search for Ultimate Weapons. |
JUL 1991 |
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| Authors:
J. Grossman; RAND CORP SANTA MONICA CA
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| Polyaniline: Inter-Relationship between Ultra-Structure and Properties |
10 JUN 91 |
7 pages |
| Authors:
Alan G. MacDiarmid; S. K. Manohar; E. M. Scherr; X. Tang; M. A. Druy; PENNSYLVANIA UNIV PHILADELPHIA DEPT OF CHEMISTRY
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| The conductivity (doped form), degree of crystallinity, tensile strength, solubility and swellability (as a gel) of polyaniline (emeraldine oxidation state) is found to be greatly dependent on the past chemical and/or mechanical history of the polymer which significantly affects the ultrastructure of the material. The conductivity and tensile strength of polyaniline films and fibers can be greatly enhanced by stretch orientation which is also accompanied by a monotonic increase in ... |
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| Indium Compounds Which Contain Two Different Organic Substituents. Crystal Structure of (In(CH2CMe3)(CH2SiMe3)Cl)2, An Interesting Case of Partial Ligand Disorder in the Solid State |
31 MAY 91 |
31 pages |
| Authors:
O. T. Beachely Jr.; John D. Maloney; Melvyn R. Churchill; Charles H. Lake; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| Three new indium compounds which contain two different organic substituents, In(CH2CMe3)(CH2SiMe3)Cl, In(CH2CMe3)(C6H5)Cl, and (Me3CCH2) (Me3SiCH2)InPEt2 have been prepared, purified and characterized. All compounds were characterized by partial elemental analysis (C, H and P as appropriate), cryoscopic molecular weight studies in benzene solution as well as NMR and IR spectroscopic studies. All compounds exist as dimeric molecules in solution. NMR spectral data were consistent with the presence of mixtures of cis ... |
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| Ultraviolet Stability of Polymers Containing the Hexafluoroisopropylidene Group |
31 MAY 91 |
10 pages |
| Authors:
C. E. Hoyle; R. Nagarajan; E. T. Anzures; P. E. Cassidy; K. M. Kane; UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE
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| The photodecomposition of four polymer series containing the hexafluoroisopropylidene (6F moiety was studied. We report herein the photostability of a poly(ether ketone) series when subjected to UV light in air. Replacement of isopropylidene with 6F results in decreased photostability for the PEKs as evidenced by changes in molecular weight and IR and UV-VIS spectra. Results for polyamides, Polyimides, and polyarylates are also under study. |
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| Methylene Bridged Group 13-15 Compounds, R2MCH2PPh2 (R = CH2CMe3, CH2SiMe3; M = Ga, In). Crystal Structure of ((Me3CCH2)2InCH2PPh2)2.C6D6, a Molecule Containing an In-C-P-In-C-P Ring in a Chair Conformation |
17 MAY 91 |
30 pages |
| Authors:
O. T. Beachley Jr.; Michael A. Banks; Melvyn R. Churchill; William G. Feighery; James C. Fettinger; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| A series of compounds of the type R2MCH2PPh2 (R = CH2CMe3, CH2SiMe3; M = Ga, In) have been prepared by metathetical reactions between the appropriate diorganometal halide and LiCH2PPH2 in pentane or Et2O at -78 C. All compounds were characterized by physical properties, partial elemental analyses (C, H), cryoscopic molecular weight measurements in benzene solution as well as IR, H NMR and P NMR spectroscopic data. All appropriate data support ... |
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| Molecular Dynamics Simulation of Substituted Polyacetylenes |
03 MAY 91 |
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| Authors:
X. F. Sun; S. B. Clough; S. K. Tripathy; G. L. Baker; LOWELL UNIV MA DEPT OF CHEMISTRY
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| Molecular mechanics and molecular dynamics calculations have been applied to several substituted polyacetylenes. Results for the barrier height for single bond rotation for polyacetylene were compared to experimental values and quantum mechanics results for low molecular weight models of polyacetylene in order to check the methodology. For poly(1-trimethylsilyl-1-propyne) barriers for rotation about a backbone single bond are approximately 40 kcal/mol. Thus the chain conformation achieved during polymerization will be maintained, ... |
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| Preparation and Degradation of Polysilylenes |
02 MAY 91 |
35 pages |
| Authors:
Krzysztof Matyjaszewski; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF CHEMISTRY
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| Mechanistic aspects of preparation and degradation of polysilylenes (polysilanes) are discussed. Reductive coupling of disubstituted dichlorosilanes at ambient temperatures in the presence of ultrasound leads to monomodal polymers with relatively narrow molecular weight distributions (M sub w/M sub n from 1.2 to 1.5) and relatively high molecular weights (M sub N from 50,000 to 100,000). Ring-opening polymerization of cyclotetrasilanes initiated with carbanions and silyl anions provides polymers with molecular weights ... |
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| The Polyanilines: A Novel Class of Conducting Polymers |
01 MAY 91 |
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| Authors:
A. G. MacDiarmid; A. J. Epstein; PENNSYLVANIA UNIV PHILADELPHIA DEPT OF CHEMISTRY
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| The conductivity (doped form), degree of crystallinity, tensile strength and solubility of polyaniline (emeraldine oxidation state) is found to be greatly dependent on the past chemical and/or mechanical history of the polymer which significantly affects the ultra-structure of the material. The conductivity of the polymer increases monotonically with increase in molecular weight up to a value of 160,000 (G.P.C.;Mp) after which it is essentially constant. A new form of polyaniline ... |
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| A Model to Describe Oil Loss Under Vacuum Conditions |
14 APR 91 |
37 pages |
| Authors:
D. J. Carre; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
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| A computer model of oil loss under vacuum conditions has been generated. The model is based on empirically determined vapor pressures and, thus, loss rates of a homologous series of straight-chain hydrocarbons. Several hypothetical oil distributions, i.e., component percentages vs molecular weights, are discussed in terms of bulk vapor pressure and oil loss. The use of the vapor pressure of unused oil to calculate oil loss rates is shown to ... |
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| Processable Polymers and Copolymers of 3-Alkylthiophenes and Their Blends |
12 APR 91 |
8 pages |
| Authors:
Martin Pomerantz; John J. Tseng; Hong Zhu; Steven J. Sproull; John R. Reynolds; TEXAS UNIV AT ARLINGTON CENTER FOR ADVANCED POLYMER RESEARCH
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| Poly(3-alkylthiophenes) have been prepared using anhydrous FeCL3 while dry air was bubbled through the reaction mixture. Molecular weight studies via GPC, using polystyrene standards in conjunction with RI and UV detection along with absolute determinations using a multiangle laser light scattering (MALLS) detector, have shown these materials are of high molecular weight(Mw of up to 400,000) and relatively low polydispersity (Mw/Mn <3). Further, the MALLS detector (absolute molecular weights) provides ... |
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| Electroactive, Near Infrared Absorbing Nickel Bis(dithiolene) Complex Polycarbonates and Polyurethanes |
12 APR 91 |
47 pages |
| Authors:
Fei Wang; Yong-Jian Qiu; John R. Reynolds; TEXAS UNIV AT ARLINGTON CENTER FOR ADVANCED POLYMER RESEARCH
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| A new series of polycarbonates and polyurethanes, containing nickel bis(dithiolene) (Ni-BDT) complexes in the main chain, have been synthesized via polymerization of a functionalized Ni-BDT complex. These polymers are highly soluble in common organic solvents, and free-standing films can be cast from solution. Gel permeation chromatographic analysis on these polymers indicates hydrodynamic volumes comparable to polystyrene standards having weight average molecular weights (Mw) ranging from 1.35 x 10 to the ... |
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| Molecular Engineering of Liquid Crystal Polymers by Living Polymerization. 14. Synthesis and Characterization of Binary Copolymers of Omega-4-Cyano-4'-Biphenyl)oxyAlkyl Vinyl Ethers Containing Undecanyl and Hexyl, Pentyl and Propyl, and Undecanyl and Prop |
10 APR 91 |
37 pages |
| Authors:
Virgil Percec; Myongsoo Lee; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
|
| Copolymerization represents the simplest synthetic technique which can be used to tailor make phase transitions of both main chain and side chain liquid crystalline polymers. Indeed, copolymerization was frequently employed to manipulate the phase transitions of side chain liquid crystalline polymers. However, most of the results reported in the literature can be considered only in a qualitative way, since there are only very few cases in which information about both ... |
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| Molecular Engineering of Liquid Crystal Polymers by Living Polymerization 11. Synthesis and Characterization of Poly 911-994-Cyano-4'- trans-a- Cyanostilbene)oxy)undecanyl Vinyl Ether) |
10 APR 91 |
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| Authors:
V. Percec; A. S. Gomes; M. Lee; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
|
| A convenient method for the synthesis of 11-(4-cyano-4'-trans-alpha- cyanostilbene)oxyundecanyl vinyl ether (6) which is the first member of a new class of mesogenic monomers is described. The polymerization of 6 initiated with CF3SO3H/S(CH3)2 in methylene chloride at proceeds through a living cationic mechanism leading to polymers with controllable molecular weights and polydispersities narrower than 1.10. The mesomorphic behavior of both 6 and poly(6)s with various molecular weights was determined by ... |
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| Ferroelectric Thin Film Research in France, |
05 APR 1991 |
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| Authors:
P. Gaucher; S. P. Faure; P. Barboux; THOMSON-CSF ORSAY (FRANCE)
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| After a review of the research made on thin film deposition in France, this work presents the comparison between two chemical deposition methods for PZT films : sol-gel method based on low molecular weight precursors and solvent, and MOD Metallo-Organic Deposition) process based on a hydrophobic solvent. The influence of the viscosity of the solvent and of the solubility of water is shown with regard to stability and drying properties. ... |
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| Synthesis of Energetic Single Phase and Multi-Phase Polymers |
31 MAR 91 |
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| Authors:
H. G. Adolph; L. A. Nock; NAVAL SURFACE WARFARE CENTER SILVER SPRING MD
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| The synthesis of ABA polymers with nitropolyformal and azidopolyether soft blocks and alkane hard blocks was continued. A higher molecular weight, isocyanate-terminated C30 hydrocarbon hard block was synthesized and characterized. Higher energy polyformal soft blocks were synthesized by copolymerization of a tetranitrodioxatridecanediol and a hexanitrodioxadiazapentadecanediol. 300 grams of tetranitrodioxatridecanediol polyformal were prepared for use in ABA polymer synthesis. This polyformal was chain-extended with phosgene to increase its molecular weight. ... |
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| Polyaniline: Oriented Films and Fibers |
18 MAR 91 |
6 pages |
| Authors:
E. M. Scheer; A. G. MacDiarmid; S. K. Manohar; J. G. Masters; Y. Sun; PENNSYLVANIA UNIV PHILADELPHIA DEPT OF CHEMISTRY
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| The dependency of the conductivity of polyaniline (emeraldine oxidation state) on its molecular weight has been determined. Uni- and biaxially oriented films and uniaxially oriented fibers of emeraldine base have been studied and the dependency of their degree of crystallinity, tensile strength, and conductivity (after doping) on draw ratio has been determined. |
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| Dissolution of Poly(p-hydroxystyrene): Molecular Weight Effects |
22 FEB 91 |
14 pages |
| Authors:
Treva Long; Ferdinand Rodriguez; CORNELL UNIV ITHACA NY SCHOOL OF CHEMICAL ENGINEERING
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| Dissolution rates of PPHS films were measured in aqueous base solvents and in 4-methyl-2-pentanone (MIBK) using laser interferometry. Molecular weights from 6,000 to 100,000 were employed. The films were spun on silicon wafers from MIBK solutions and baked 1 hour at 160 C. The most striking feature of dissolution behavior is the peculiar way in which rate varies with molecular weight. Below a molecular weight of about 20,000, the rate ... |
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| Synthesis of Segmented Anisotropic-Isotropic Poly(Aryl Ester)Poly(Arylene Ether) Copolymers, |
FEB 1991 |
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| Authors:
J. E. McGrath; K. L. Cooper; W. Waehamad; H. Huang; G. L. Wilkes; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG
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| Carboxyl functional poly(arylene ether) oligomers of controlled number average molecular weight were synthesized via nucleophilic aromatic substitution step polymerization using p-hydroxy benzoic acid as the molecular weight and end group controlling reagents. The subsequent functionalized polyarylene ethers were copolymerized with acetoxy benzoic acid or acetoxy-phenoxy benzoic acid via melt acidolysis procedures. Successful copolymers were generated using chlorobenzene as a solvent for the first stage of the reaction followed by melt ... |
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| Energetic Binders for Plastic Bonded Explosives. |
29 JAN 1991 |
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| Authors:
HORST G. ADOLPH; Judah Goldwasser; G. W. Lawrence; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This patent discloses an energetic uncured binder composite mixture comprising: (1) a hydroxy-terminated polyfluoroformal prepolymer of the general formula HOCH2(CF2)nCH2-(OCH2OCH2(CF2)nCH2-)mOH wherein n is 3 or 4 and m is selected to provide a number average molecular weight of from about 1,000 to about 10,000 for the prepolymer; and (2) an energetic plasticizer which is bis(2,2-dinitropropyl)formal, bis(2,2-trinitroethyl)formal, bis(2-fluoro-2,2-dinitroethyl)formal, bis(2,2-difluoro-2-nitroeethyl)formal, 2,2-dinitropropyl 2-fluoro-2,2-dinitroethyl formal, or mixtures thereof; wherein the weight ratio of energetic ... |
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| Evaluation of Domain Spacing Scaling Laws for Semicrystalline Diblock Copolymers |
28 JAN 91 |
21 pages |
| Authors:
K. C. Douzinas; R. E. Cohen; A. F. Halasa; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
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| Diblock copolymers of (ethylene-co-butylene)-b-(ethylene) (EBEE) were used to evaluate scaling laws describing the molecular weight dependence of the lamellar domain spacing of semi-crystalline block copolymer systems. Small angle X-ray scattering was used to measure lamellar domain spacings for a series of EBEE samples. Experimental results were in good agreement with the predictions of the equilibrium theory of Whitmore and Noolandi. |
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| Diphenylphosphide Derivatives of Bisneopentyl-Gallium and -Indium. Crystal and Molecular Structures of ((Me3CCH2)2GaPPh2)2 and ((Me3CCH2)2InPPh2)3 |
18 JAN 91 |
36 pages |
| Authors:
Michael A. Banks; O. T. Beachley Jr.; Lisa A. Buttrey; Melvyn R. Churchill; James C. Fettinger; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| The two compounds, (Me3CCH2) 2MPPh2 (M=Ga, In) have been prepared by metathetical reactions between (Me3CCH2)2MCl and KPPh2 and fully characterized. The characterization data include elemental analyses (C,H), melting points, IR, H and P NMR spectral studies, cryoscopic molecular weight studies in benzene solution and single crystal X-ray structural studies. The gallium compound exists as a dimer in benzene solution and in the solid state. |
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| Chain Propagation/Step Propagation Polymerization. Regular Thermoplastic Elastomers |
15 JAN 91 |
3 pages |
| Authors:
K. B. Wagener; FLORIDA UNIV GAINESVILLE DEPT OF CHEMISTRY
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| This research has produced a new polymer synthesis technique for generating well defined segmented thermoplastic elastomers. Chain propagation using ring opening chemistry has been coupled with step propagation techniques to create solvent resistant segmented elastomers, wherein each segment possesses a narrow molecular weight distribution. |
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| Supercritical Fluid Processing of Propellant Polymers |
JAN 91 |
62 pages |
| Authors:
James J. Watkins; Val J. Krukonis; PHASEX CORP LAWRENCE MA
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| Polymeric pre-propellant binders are known to be heterogeneous materials exhibiting significant variation with respect to molecular weight, structure, functionally, and related performance properties. The objective of this program was to demonstrate the feasibility of fractionating propellant binders with supercritical fluid (SCF) solvents. Hydroxy-terminated polybutadiene (HTPB) (R-45M, Atochem North America) was fractionated with supercritical propane yielding ten fractions with number average molecular weights ranging from 780 to 11760 and polydispersities of ... |
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