A method based on the pressure dependence of the bulk modulus was developed for determining the Lattice Gruneisen Constant, yL, of polymers. This technique was applied to a series of polymers and the results indicated that yL for most polymers lies between 4 and 9. These results were discussed in terms of the anharmonic properties of polymers and, in particular, in terms of the interchain specific heat. ZUSAMMENFASSUNG:Eine auf der Druckabhangigkeit des Kompressionsmoduls beruhende Methode zur Bestimmung der Gitter-Gruneisen-Konstanten, yL, von Polymeren wurde entwickelt. Sie wurde auf eine Reihe von Polymeren angewandt, wobei sich zeigte, da8 fur die meisten Polymeren yL zwischen 4 und 9 liegt. Diese Resultate wurden im Zusammenhang mit den anharmonischen Eigenschaften von Polymeren diskutiert, insbesondere mit der intermolekularen spezifischen Warme von Polymerketten.

The ultrasonic absorption of a 30% mole fraction mixture of dimethyl sulfoxide (DMSO) and water was measured at frequencies from 5 to 200 MHz by a pulse echo technique and over the temperature range −80 to 25 °C. At temperatures above −55 °C the observed absorption is greater than the classical value and is due to volume viscosity. To a very good approximation the ratio of the volume viscosity ηv to the shear viscosity ηs is 2/3. Below −55 °C a simultaneously occuring shear and volume relaxation is observed and the data in this region can be fit with a single relaxation time with an activation energy of 7.3 kcal/mol in agreement with that obtained for other hydrogen bonded liquids. No evidence of a distinct DMSO–water complex has been found.

Measurements of the temperatwe dependence of volume resistivity of a variety of polymers are used to elucidate polymer structure and the mechanism of electrical conduction ne of the more important measurements made by 0 those investigating high polymers is that of the magnitude and temperature dependence of the electrical volume resistivity. Such data can be used to calculate the activation energy, E,, for the electrical conduction process in the polymer and to estimate the extent of polymerization. The magnitude and temperature dependence of the electrical resistivity (or conductivity) of a polymer is a function of the molecular structure of the polymer, the nature and number of the current carriers, and the temperature. Resistivity determinations have been used for many years by physicists in studying the structure of both elements and inorganic compounds (1), and more recently they have been applied to solid organic compounds ( 2 ) . However, the use of this measurement on high polymers has not been widespread. A number of years ago studies by Fuoss (3) and by Baker and Yager (4) utilized the temperature dependence of the resistivity as an aid in studying the molecular structure of polymers. Following their work, use of the technique has slowly become more widespread. However, the literature still does not contain any significant amount of accurate data on the magnitude and temperature dependence of the electrical resistivities of thermoplastic and thermosetting polymers. Such information is of great importance not only in technological applications of these materials but also in theoretical investigations. The values reported here and the experimental technique are of interest to those considering the possibility of employing modified polymers (5) as organic semiconductors. These data could also serve as an index for the characterization of polymers. In addition to the experimental work and data reported here, the available literature values for the temperature dependence of the resistivity of various polymers are also included. TheoreticalThe theoretical basis for calculating the activation energy, E,, of the electrical conduction process has been developed by Glasstone, Laidler, and Eyring ( 6 ) who have shown that the concepts used in chemical kinetic 80 studies can be successfully applied to physical processes. The change in the electrical resistivity of a polymer with temperature can be considered to be a rate process similar to those encountered in chemical kinetic studies and the same equations can be applied to both chemical and physical rate processes.Equation ( 1 ) is used to calculate the activation energy for the conduction process.where p is the resistivity, A, is a temperature independent constant, R is the molar gas constant 1.987 cal/degmole, T is the absolute temperature, and E, is the activation energy for the conduction process. Many investigators have studied the electrical conduction process in high polymers, (3, 7) and the evidence is that conduction is an ionic process. Ions stem from t...

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Bulk compressibilities of a series of linear and crosslinked polymers have been measured, in a Matsuoka‐Maxwell apparatus, at pressures up to 10,000 atmospheres and at temperatures to 202°C. These polymers exhibited nonlinear compressibility characteristics and a maximium compressibility of about 15% at 10,000 atmospheres. At slow loading rates, data were obtained for the amorphous polymers which could be expressed as glass‐rubber phase gisgrams. The nature of the observed compressibilities are discussed and the usefulness of the data is indicated.