Accession Number : AD0622126

Title :   SHEAR-RELAXATION PROCESSES IN LIQUIDS,

Corporate Author : LOCKHEED MISSILES AND SPACE CO PALO ALTO CALIF LOCKHEED PALO ALTO RESEARCH LAB

Personal Author(s) : Knollman,G. C. ; Miles,D. O. ; Hamamoto,A. S.

Report Date : 19 APR 1965

Pagination or Media Count : 11

Abstract : Both cooperative behavior, involving breakup and reformation of molecular aggregates, and environmental dissimilarities, attributed to incompleteness of shortrange order, have been proposed earlier by two of the authors as possible mechanisms giving rise to the distribution of shear-relaxation times exhibited by most liquids. Experimental evidence is presented giving qualitative indication that environmental-dissimilarity effects indeed can be operative in a liquid together with cooperative phenomena. Shear-relaxation characteristics are studied at a number of temperatures for a host liquid, hexachlorobiphenyl, having methanol and toluene in various concentrations as separate impurity liquids. Small amounts of the additive liquids are found to lessen the decay rate of cooperative behavior with increasing temperature, a result attributed to both degraded cooperative behavior and an environmental-dissimilarity mechanism. Although cooperative behavior predominates throughout the temperature and concentration range investigated, in the low-temperature region the impurity additive primarily decomposes aggregates of cooperative molecules, whereas at higher temperatures the impurity markedly enhances environmental dissimilarities and the distribution function widens with increasing (small) concentration. Toluene impurity additive displays greater degradation effect on cooperative behavior as well as greater enhancement of environmental dissimilarities than does methanol. (Author)

Descriptors :   (*SHEAR STRESSES, LIQUIDS), (*RELAXATION TIME, SHEAR STRESSES), PERTURBATION THEORY, KINETIC THEORY, DIELECTRIC PROPERTIES, IMPURITIES, AROMATIC COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE