A New Investigation of Tetrahydrofuran-Based Polyether Glycols in Urethane Elastomers

1980 ◽  
Vol 53 (5) ◽  
pp. 1032-1040 ◽  
Author(s):  
E. Pechhold ◽  
G. Pruckmayr ◽  
I. M. Robinson
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Room Temperature ◽  
Hydrolytic Stability ◽  
Cyclic Ether ◽  
The Other ◽  
Temperature Behavior ◽  
Oil Resistance ◽  
Soft Segments ◽  
Better Than

Abstract Random copolyether glycols with 50 mole % EO and low cyclic ether content represent novel soft segments for polyurethanes, and have some advantages over the other soft segments as shown in Table V. THF/EO copolyether glycols are easier to handle and to process because they are liquids at room temperature and exhibit lower viscosities and better diol compatibility. Physical properties of polyurethanes made from THF/EO copolyether glycols are comparable to those made from other soft segments; the hydrolytic stability and low temperature behavior are superior to polyester and polycaprolactone glycols, and solvent/oil resistance is better than PTMEG. THF/EO copolyether glycol is a replacement for PTMEG only with reformulation; it could be considered for applications which require better solvent/oil resistance or easier handling and processability.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

Newly Developed Heat Resistant Magnesium Alloy by Thixomolding®

2005 ◽  
Vol 488-489 ◽  
pp. 287-290 ◽  
Author(s):  
Tadayoshi Tsukeda ◽  
Ken Saito ◽  
Mayumi Suzuki ◽  
Junichi Koike ◽  
Kouichi Maruyama
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Die Casting ◽  
The Other ◽  
Heat Resistant ◽  
Higher Temperature ◽  
Better Than

We compared the newly developed heat resistant magnesium alloy with conventional ones by Thixomolding® and aluminum alloy by die casting. Tensile properties at elevated temperatures of AXEJ6310 were equal to those of ADC12. In particular, elongation tendency of AXEJ6310 at higher temperature was better than those of the other alloys. Creep resistance of AXEJ6310 was larger than that of AE42 by almost 3 orders and smaller than that of ADC12 by almost 2 orders of magnitude. Fatigue limits at room temperature and 423K of AXEJ6310 was superior among conventional magnesium alloys.

Dynamisches Verhalten dimerer 1,3,2,4λ2-Diazasilastannetidine und -plumbetidine in Lösung — eine Multikern-NMR-Studie/Dynamic Behaviour of Dimeric 1,2,3,4λ2-Diazasilastannetidines and -plumbetidines in Solution — a Multinuclear NMR Study

1989 ◽  
Vol 44 (3) ◽  
pp. 288-292 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Klaus Horchler ◽  
Hong Zhou ◽  
Michael Veith
Keyword(s):  
Low Temperature ◽  
Dynamic Process ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
The Other ◽  
Multinuclear Nmr ◽  
Nmr Data ◽  
Nmr Study ◽  
Intramolecular Process

1,3-Diisopropyl-2,2-dimethyl-1,3,2,4λ2-diazasilastannetidine (1b) and -plumbetidine (2b) are dimeric [(1b)2, (2b)2] in solution. At room temperature the structure of (1b)2 is fluxional. The dynamic behaviour is interpreted - on the basis of 1H. 13C, 29Si and 119Sn NMR data - as an intramolecular process in which the four-membered rings keep their identity. Such a process involves either concerted opening of the two coordinative Sn - N bonds and mutual slippage of the two rings, or consecutive cleavage of one of the coordinative Sn - N bonds and rotation about the other one. At room temperature the dimer (2b)2 is in equilibrium with its monomer 2b, whereas at low temperature the dynamic process corresponds to that established for (1b)2. In solutions which contain a mixture of the dimers (1b)2 and (2b)2, the presence of the mixed dimer 1b/2b can be proved unambiguously by consistent 29Si, 119Sn and 207Pb NMR data.

Crystallization in Unstretched Rubber. Microscopic Study in Polarized Light

1951 ◽  
Vol 24 (3) ◽  
pp. 550-556
Author(s):  
H. N. Campbell ◽  
M. D. Allen
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Melting Temperature ◽  
Microscopic Study ◽  
Room Temperature ◽  
Polarized Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Limited Mobility ◽  
Sensitive Method

Abstract Since many elastomers indicate by their physical properties that crystallization occurs even when such crystallization is not detectable by x-ray diffraction, a direct microscopic study in polarized light was undertaken. This study confirms the presence of such crystallinity not only in rubber but also in polybutadiene and some low-temperature copolymers. Furthermore, the same crystal pattern is reproduced on melting and refreezing provided the intermediate melting temperature is not too high. This indicates that x-ray diffraction is not a very sensitive method for detecting small amounts of crystallinity in high polymers. The reproduction of the crystal pattern on refreezing shows that the molecular segments have limited mobility even at room temperature; this may require revision of current theories of the origin of retractive forces in elastomers.

Trihapto cycloheptatrienyl molybdenum and tungsten dicarbonyl compounds incorporating tridentate chelating dimethyl(1-pyrazolyl)(ethanolamine)gallate ligands

1980 ◽  
Vol 58 (21) ◽  
pp. 2278-2285 ◽  
Author(s):  
Kenneth S. Chong ◽  
Alan Storr
Keyword(s):  
Nitrogen Atom ◽  
Low Temperature ◽  
Physical Properties ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Amino Nitrogen ◽  
Nmr Studies ◽  
Dicarbonyl Compounds ◽  
H Nmr ◽  
And Tungsten

The synthesis and physical properties of a series of cycloheptatrienyl molybdenum and tungsten dicarbonyl compounds incorporating dimethyl(1-pyrazolyl)(ethanolamine)gallate ligands have been investigated. The monomeric, pseudo octahedral, complexes have the organogallate ligand occupying a set of facial positions with the cycloheptatrienyl ring situated opposite to the amino nitrogen atom. Proton nmr studies have shown the η3-C7H7 ligand of the complexes to be fluxional in solution at room temperature. In the low temperature limiting 1H nmr spectra of the complexes in solution, however, it is possible to distinguish ail seven protons of the static η3-C7H7 ring owing to the asymmetric nature of the octahedral molecules.

Low-temperature phases of dicalcium barium hexakis(propanoate)

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Jan Fábry ◽  
Michal Dušek
Keyword(s):  
Low Temperature ◽  
Phase I ◽  
Room Temperature ◽  
High Temperature Phase ◽  
The Other ◽  
Phase Iii ◽  
Temperature Phase ◽  
Acta Cryst ◽  
Carboxylate Groups ◽  
Structure Determinations

The structure determinations of phases (II) and (III) of barium dicalcium hexakis(propanoate) {or poly[hexa-μ4-propanoato-bariumdicalcium], [BaCa2(C3H5O2)6] n } are reported at 240 and 130 K, respectively [phase (I) was determined previously by Stadnicka & Glazer (1980). Acta Cryst. B36, 2977–2985; our structure determination of phase (I) at room temperature is included in the supporting information]. In the high-temperature phase, the Ba2+ cation is surrounded by six carboxylate groups in bidentate bridging modes. In the low-temperature phases, five carboxylate groups act in bidentate bridging modes and one acts in a monodentate bridging mode around Ba2+. The Ca2+ cations are surrounded by six carboxylate O atoms in a trigonal antiprism in all the structures. The Ba2+ and Ca2+ cations are underbonded and significantly overbonded, respectively, in all the phases. The bonding of the Ba2+ cation increases slightly at the cost of the bonding of Ca2+ cations during cooling to the low-temperature phases. The phase transitions during cooling are accompanied by ordering of the ethyl chains. In room-temperature phase (I), all six ethyl chains are positionally disordered over two positions in the crossed mode, with additional splitting of the ethyl α- and β-C atoms. In phase (II), on the other hand, there are three disordered ethyl chains, one with positionally disordered ethyl α- and β-C atoms, and the other two with positionally disordered ethyl β-C atoms only, and in the lowest-temperature phase (III) there are four ordered ethyl chains and two disordered ethyl chains with positionally disordered ethyl β-C atoms only.

Heat Conductivity of Rubber at Low Temperatures

1940 ◽  
Vol 13 (4) ◽  
pp. 830-830
Author(s):  
Adolf Schallamach
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Temperature Region ◽  
Heat Conductivity ◽  
Low Temperatures ◽  
Room Temperature ◽  
Tire Rubber ◽  
Order Of Magnitude ◽  
Temperature Work

Abstract While examining the possibilities of applying rubber in low temperature work, we were hampered by the lack of available data on its physical properties at low temperatures. We were aware of the difficulties to be expected in making accurate measurements in that temperature region, and this applied especially to the heat conductivity, in which we were particularly interested. To obtain at least an estimate of the order of magnitude, we carried out some measurements of the heat conductivity of commercial rubber (North British tire rubber) at room temperature and at the temperature of liquid air.

Modification of Asphalt by Block Polymers of Butadiene and Styrene

1982 ◽  
Vol 55 (5) ◽  
pp. 1389-1402 ◽  
Author(s):  
Gerard Kraus
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Physical Properties ◽  
Room Temperature ◽  
Softening Temperature ◽  
Block Polymers ◽  
Rich Phase ◽  
Block Polymer ◽  
Low Concentrations ◽  
Low Temperature Flexibility

Abstract Elastomeric thermoplastic block polymers of butadiene and styrene are highly effective in converting asphalts into truly rubber-like materials. Additions of 10–14% of these polymers to asphalt result in lower penetration values, greatly reduced flow above room temperature, increases in softening temperature to values in excess of 100°C and superior low temperature flexibility. The blends are characterized by a unique morphology in which the block polymer, swollen with the lower molecular weight constituents of the asphalt, forms a continuous lacework in a bituminous phase enriched with asphaltenes. The polymer-rich phase consists, in turn, of two microphases derived from the block polymer domain structure. At low concentrations, where the swollen polymer forms discrete inclusions in the asphaltic continuum, effects on the physical properties of the asphalt are less pronounced but can still be significant. The multiphase morphology of these composites accounts satisfactorily for the most important features of their mechanical behavior.

Thermal Diffusion in Jammed Aluminum Nanopowders

2011 ◽  
Vol 121-126 ◽  
pp. 1809-1812
Author(s):  
Ching Yen Ho ◽  
C. Ma ◽  
F. M. Sui
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Heat Transport ◽  
Surface Area ◽  
Room Temperature ◽  
Bulk Material ◽  
The Other ◽  
Insulating Material ◽  
Size Dependent ◽  
Bed Porosity

Nanoparticles show a variety of size-dependent properties due to the dramatic changes in the ratio of surface area to volume. The characteristics of nanoparticles different from the bulk material make the properties of the powders composed of these nanoparticles attract more attention. The heat transfer in the powder composed of nanoparticles is experimentally investigated in this paper. The powder is wrapped up in the slender tube made of insulating material. One end of the slender tube filled with powder is maintained at low temperature and the other end is kept at room temperature. The temperature histories at two different locations in the slender tube are recorded using thermalcouples. The results show that the heat transfer depends on the bed porosity and the thermal conductivities of the solid and the gas. The pressure on the Al powders enhances the rate of heat transport due to the decrease of the bed porosity and a small fraction of gas.

REPUBLIC HP 9-4-25

Alloy Digest ◽  
1965 ◽  
Vol 14 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Temperature Performance ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Better Than

Abstract Republic HP 9-4-25 is a heat treated alloy steel capable of developing yield strengths up to 200,000 psi with toughness characteristics better than other quench and tempered alloys. It is designed for sheet, plate and forging applications. It is also designed to be welded in the heat treated condition. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-181. Producer or source: Republic Steel Corporation.

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