A nonlinear theory of viscoelasticity of finite deformation is developed on the basis of the analytical system of approximation in the elasticity theory of finite deformation, which was re-examined and organized in Part I. The theory is derived from the elasticity theory by introducing a series of multi-time memory functions for taking account of the time dependence of viscoelasticity. There exists one-to-one correspondence between the constitutive equations in the elasticity theory and those in the present theory; the former being just like a map from the latter. The simple, plain, and concrete characters of the elasticity theory are thus inherited by the present theory, and a fortune of the elasticity theory such as ample approaches to the three dimensional analysis and accumulations of data become available for the analysis of viscoelasticity. The present theory may be valid for the analysis of deviation from the elasticity theory due to viscoelasticity and from the theory of linear viscoelasticity due to non-linearity. The theory gives the constitutive equations which corresponds to the equations of the Oth-order to the 2nd-order (Guth-Wang's approximation) in the molecular network theory of rubberlike elasticity. This suggests that the present theory may be useful for further construction of molecula theory of finite nonlinear viscoelasticity of rubberlike materials.
There was a clear difference between the apparent viscosity ηa of dispersed systems of the flue-cured tobacco and that of the air-cured tobacco. To clarify this difference, the influences of water-soluble compositions included in tobacco on ηa were examined about the systems of the flue-cured tobacco, the air-cured tobacco, and their residues treated with water, using a ram-type extruder. Since a part of water-soluble compositions of tobacco should be dissolved into the water, the concentration of the systems was expressed in terms of the ratio of weights of water and insoluble composition. Sugars, the major part of the water-soluble compositions for the flue-cured tobacco, exhibited a large effect on ηa. ηa decreased with increase of sugar content in tobacco and also with addition of sugers to the systems. The influences of the sugars were evenly observed for two varieties of tobacco and their residues. The extract of the flue-cured tobacco bore the viscosity about 13 times larger than that of water. However, as dispersion medium, the extract gave a dispersion with lower ηa than did water. On the other hand, the extract of the air-cured tobacco bore the viscosity about 3 times larger than water, and it gave a dispersion with ηa slightly higher than did water. By decationizing treatment, the viscosity η of two extracts and the apparent viscosity ηa of dispersed systems in these extracts were both decreased. The decrease in ηa were remarkable in the systems of the extract of the air-cured tobacco. There was little difference in chemical compositions between two tobaccos, after treatment with hot water. Some differences in ηa, however, was observed between systems of two residues with as yet unknown reason.
Rheo-optical experiments have been carried out to study the relationship between rheological properties and structures of concentrated solutions of PBLG (Poly-γ-Benzyl-L-glutamate) in m-cresol. The flow properties of the solutions at concentrations above B-point have been observed with a rheometer equipped with quartz cone-plate, and simultaneously the transmitted light intensities (Ix, In and IE) of polarized light have been measured on the sample under shear as functions of shear rate (3×10-2-4×100s-1). It has been found that the transmitted light intensity IE (measured under extinction position of crossed polarizers system) is the most meaningful measure to know the orientation behavior and the mesophase transition of polymer liquid crystal systems. IE is very high in the undisturbed state for all the solutions tested. In the case of a 10 wt% solution, IE becomes very low under shear even at low shear rate and rapidly decreases to zero with increasing shear rate. The transmitted light intensities Ix (with crossed polarizers) and I (with parallel polarizers) change with shear rate in a wave-like manner, indicating that the retardation changes continuously with increasing shear rate. From the results, it is concluded that in the case of the 10% solution the polydomain cholesteric structure in the undisturbed state changes easily to a continuous phase of nematic structure even at low shear rate. In the case of a 15 wt% solution, IE decreases from a high value in the undisturbed state to a lower value by shearing and remains almost constant over a certain range of shear rate, until it suddenly decreases to zero at a certain high shear rate where the system changes into a continuous nematic phase. In the case of a 20 wt% solution, IE remains at a rather high level even at high shear rate, indicating that the system undergoes polydomain flow. In the case of a 40 wt% solution, IE remains at a high value even at the highest shear rate examined, and the system is considered to flow maintaining a polydomain cholesteric structure. No large scale orientation of molecules is observed even at high shear rate. The apparent viscosity of the solutions is the lowest among the solutions tested. It is pointed out that the lower viscosity does not always mean the higher degree of molecular orientation. The recovery of IE, after cessation of the steady shear, is negligibly small, if the steady state IE has once reached nearly zero. However, the recovery of IE is quite large, when the steady state IEll has remained at a high value and the system has held its polydomain structure in flow.