Accession Number : AD0687647

Title :   LIQUID VISCOELASTICITY UNDER RARE-GAS INFUSION,

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

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

Report Date : 23 FEB 1968

Pagination or Media Count : 11

Abstract : Experimental measurements have been made of the complex frequency-dependent shear modulus for hexachlorobiphenyl (Aroclor 1260) both with and without, in turn, helium- and argon-gas infusion to capacity, over the temperature range 5-25C and the pressure range ambient atmospheric to 4000 psi. Static viscosity results derived from the data are presented and analyzed with the aid of the Macedo-Litovitz hybrid equation to find changes in relative free volume brought about by rare-gas impregnation. Limiting high-frequency shear-compliance data are also presented, to which a phenomenological formulation for shear compliance in molecular-bonded liquids is applied as a means for assessing the additional equilibrium number of intermolecular bonds that are bent or broken under rare-gas infusion. Changes are noted in dynamic shear rigidity, loss modulus, and viscoelastic relaxation times brought about by the presence of each rare-gas impregnant in the recipient liquid, all as influenced by temperature and applied static pressure. Viscoelastic relaxation times are decreased in Aroclor upon rare-gas impregnation, the reduction being more pronounced the lower the temperature or the higher the applied pressure. Infusion with the larger argon molecule has over all a more prominent impact on changes in free volume, bond density, and shear-rigidity spectra than has impregnation with helium molecules. However, no appreciable differences are detected between the two gas-infusion cases insofar as their impact on the relaxation time is concerned. (Author)

Descriptors :   (*VISCOELASTICITY, *BIPHENYL), (*SHEAR STRESSES, MOLECULAR ASSOCIATION), RARE GASES, PRESSURE, HALOGENATED HYDROCARBONS, CHLORINE COMPOUNDS

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE