Poly(ethylene sulfide). IV. A rheological method for determination of “apparent molecular weight”

By combining a number of theoretical relationships concerning the effect of molecular weight on melt rheology, an equation may be derived for conversion of melt indexer flow rate to “apparent molecular weight.” In spite of certain evident theoretical shortcomings of this derivation, the method was applied to the determination of the molecular weight of highly crystalline insoluble poly(ethylene sulfide), for which no other method appeared to be satisfactory. When applied to polymer specimens of presumably known molecular weight (e.g., certain ionically initiated specimens), reasonable agreement was found.