摘要:

A method for measuring the pressure exerted by rubber on the walls of the die of a tubing machine is described. An extrusion plastometer was used in these pressure measurements and the results obtained were employed in correlating the plastometer with a tube tubing machine. This was accomplished by determining the isothermal curve of efflux ratevs.pressure for the tubing machine and comparing with that for the extrusion plastometer. The measured values of the pressure at various speeds and temperatures of extrusion should be of value in the design of new types of extruding machines.

ISSN:0021-8979    

DOI:10.1063/1.1745286

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

Although a simple exponential type of equation such as that given by Saal and Koens may give an approximation suitable for many practical purposes, it does not relate the viscosity and penetration of asphalts with the accuracy warranted by the experimental data. An accurate correlation would require a much more complicated equation which would be of doubtful practical value. Asphalts obtained from different sources or those prepared or processed differently require distinctly characteristic constants in the equation proposed by Saal and Koens. This is true no matter whether the change in consistency is due to variations in the temperature of testing or in the method or extent of processing. An asphalt brought to a given penetration by regulating the temperature does not necessarily have a viscosity identical with that of the same type of asphalt having that penetration at a different temperature.

ISSN:0021-8979    

DOI:10.1063/1.1745287

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

A series of modified Ostwald viscometers is described. They are shown experimentally to have a time of flow that is proportional to the kinematic viscosity when they are used with petroleum oils of a viscosity between 2.17 and 1280 centistokes.

ISSN:0021-8979    

DOI:10.1063/1.1745288

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

The fluidities of mixtures of benzoic acid and naphthalene with benzyl benzoate have been measured to show that it is possible to estimate the fluidity and association of benzoic acid and naphthalene below their melting points in a variety of ways; first, by using the undercooled liquid; second, by extrapolating the fluidity curve of the liquid; third, by extrapolating from a mixture to the pure substance in the undercooled state, and possibly in several solvents; fifth, by measurement of the various derivatives of the compound and extrapolating the association back to the mother substance; or, sixth, by measurement of other homologs in the same series, and extrapolating to the desired member. In this paper the last method is shown to be the most satisfactory. How far the method may be extended remains to be seen. Some such method must be resorted to in estimating the fluidity and association of substances which cannot be obtained in the fluid condition at the temperatures at which the fluidity is desired. The authors predict the fluidity curves of oxalic and malonic acids in the anhydrous form. The first does not melt before decomposing and the second is unstable. The method makes it desirable to obtain values of the association for representatives of the different classes of chemical compounds. The method may then be of practical use in obtaining the molecular weights of substances of very high molecular weight, particularly of substances of high association.

ISSN:0021-8979    

DOI:10.1063/1.1745289

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

The viscosities of four samples of pure molten boron trioxide have been measured between 267° and 443°C with a concentric cylinder viscometer. The results, representing true viscosity, range from 2.1×1011to 2.1×105poises and are consistent with earlier data obtained at much higher temperatures. A viscosity value in the neighborhood of 1013to 1014poises appears to be associated with the so‐called transition region in this and other glassy, or amorphous, materials.

ISSN:0021-8979    

DOI:10.1063/1.1745290

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

The effects of pressure and temperature change on the viscosity of organic, binary mixtures have been investigated by methods developed and used by P. W. Bridgman. Six mixtures have been examined over the entire concentration range at two temperatures, 30° and 75°C, and at pressures extending to 12,000 kg/cm2. The isobaric, log viscosity‐concentration curves forn‐hexane carbon disulphide, andn‐hexanen‐decane are linear at both temperatures, indicating that these mixtures obey Arrhenius' empirical equation for the viscosity of a binary mixture. It is believed that a comparatively simple type of interlocking among molecules occurs in these mixtures due to the effectively linear structure of the molecules and the absence of non‐uniform molecular fields such as would cause some sort of association. For the remaining mixtures:n‐hexane diethyl ether,n‐hexane chlorobenzene,n‐pentane benzene, and eugenol carbon disulphide, the corresponding viscosity isobars are more complex; irregularities occur in certain regions of concentration which vary with temperature and pressure. In these latter mixtures, the interlocking at high pressures is complicated by the structural differences of the component molecules and their effects. The viscosity ofn‐decane as a function of pressure and temperature has also been investigated. Density data at atmospheric pressure and 30° are included in the paper.

ISSN:0021-8979    

DOI:10.1063/1.1745291

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1745292

出版商:AIP    

年代:1935

数据来源: AIP