Rheological and physical properties of modified polyimides with different rigidities

Abstract

Advances in the theory of polymer solution dynamics have been associated with establishing a relation between the macroscopic hydrodynamic property of a polymer solution and the polymer structure. A polymer theory developed by Kholodenko, which is based on the analogy between the semiflexible polymer and Dirac fermions is applicable to a semiflexible polymer with an arbitrary flexibility ranging from a fully flexible polymer to a completely rigid polymer. This theory is modified and applied experimentally to characterize the persistence length (the flexibility) from the intrinsic viscosity data without major departure from the already developed formalism. In CHAPTER I, the Kholodenko``s theory is explained and emphasized as an outstanding feature. In fact, this theory is based on the chain walk model with a finite length (cutoff), and only correlates the moment of statistical averages with the chain conformation. It represents the chain conformation with the persistence length and the contour length. It is derived on the assumption of the equilibrium state and is independent on the hypothetical modeling to calculate the detailed hydrodynamic properties of polymer solution. Therefore, it can be incorporated into any kind of hypothetical model to calculate the macroscopic properties of semiflexible polymer solution. The original paper of Kholodenko showed briefly that the limiting cases of flexible coil and rigid rod by adopting Zimm model were matched well with the well-known results of previous theories even though it was driven from the completely different points of view. However, it is difficult to predict the hydrodynamic property of a polymer solution and compare with the actual experimental results by the Kholodenko``s theory in its original form. This is due to fact that the Dirac propagator was 1+1 dimensional one and did not specify the role of cutoff length in the calculation of hydrodynamic property of the polymer solution with an arbitrary persisten...