Temperature and pressure dependence of the specific volume of polymers—I. Polymethyl methacrylate

1964 ◽  
Vol 5 (6) ◽  
pp. 986-994 ◽  
Author(s):  
S.A. Arzhakov ◽  
G.L. Slonimskii ◽  
B.P. Shtarkman ◽  
V.A. Kargin
Author(s):  
S Bair

A thorough characterization of all viscous flow properties relevant to steady simple shear was carried out for five liquid lubricants of current interest to tribology. Shear stresses were generated to values significant to concentrated contact lubrication. Two types of non-Newtonian response were observed: shear-thinning as a power-law fluid and near rate-independence. Functions and parameters were obtained for the temperature and pressure dependence of the viscosity and of the time constant for the Carreau-Yasuda equation. Results are consistent with free volume and kinetic theory, but directly contradict many assumptions currently utilized for numerical simulation and for extracting rheological properties from contact measurements.


2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj


1979 ◽  
Vol 52 (2) ◽  
pp. 294-303 ◽  
Author(s):  
R. Caspary ◽  
P. Kretschmer

Abstract The dependence of the Index of Elasticity, E, the reciprocal value of sound velocity, on temperature and pressure is related to specific volume and compressibility of rubbers. The sensitivity of E towards changes of temperature and pressure was calculated, indicating a new versatile possibility for the control of rubber extruders. To confirm this, extruder experiments were carried out with an SHR compound, of which a working diagram was established showing the complete behavior of E=f(p,T). The effect of compound composition, especially of plasticizer and carbon black content, was examined. Viscosity in the extruder primarily determines changes in E. The method was shown to be applicable up to a die diameter of at least 200 mm. The method may also be applied to follow degradation of rubber compounds during mastication.


Author(s):  
Florian Pabst ◽  
Zaneta Wojnarowska ◽  
Marian Paluch ◽  
Thomas Blochowicz

The temperature and pressure dependence of two dynamic processes in the dielectric spectra of five supercooled ionic liquids equipped with octyl-chains are reported. The microscopic origin of these processes is discussed.


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