Characterization of Very Pauci-Disperse Systems with Strong Interaction by Equilibrium Sedimentation. Part I. Determination of Molecular Weights and Partial Evaluation of Interaction Matrix

摘要

Aromatic-heterocyclic polymers are a class of interesting materials that are currently being developed due to their resistance to high temperature. Relatively little has been done toward determining many of the fundamental parameters that govern the physical behavior of these chains. This report covers one phase of an investigation of the dilute solution properties of one of the earlier, high molecular weight aromatic-heterocycles, poly(2,2'-m-phenylene-5,5'-bibenzimidazole) (PBI), DISSOLVED IN A GOOD SOLVENT DIMETHYLACETAMIDE (DMAC). Specifically this report concerns equilibrium sedimentation measurements on samples of this polymer in an effort to define molecular weight, and polymer-polymer interaction parameters. Preliminary measurements on these samples suggested that each sample consists of a relatively small number of rather discrete molecular weight ranges. In addition, it was suspected that relatively strong interactions could exist between various species. Therefore, early consideration was given to describing this situation by applying a method developed from study of pauci-disperse systems. (Author)