CORRELATIONS BETWEEN THE TRANSVERSE MECHANICAL AND SHEAR PROPERTIES IN HIGHLY ORIENTED LIQUID-CRYSTAL COPOLYESTERS

Measurements of the transverse extensional compliance S-11 of highly o riented films of two liquid-crystal copolyesters are reported over a w ide range of temperature and frequency. These results are compared wit h measurements of the shear compliance S-44 to show that there is a si mple linear relationship between S-11 and S-44 over a wide temperature range. Models based on stiff fibres or on laths embedded in an isotro pic incompressible matrix are advanced. These are instructive in provi ding some physical understanding on the basis that S-11 is determined by shear within the structure.