| Abstract: | A method and apparatus for measuring the elastic and other properties of polymers in the melt state is presented. The recoverable strain magnitude and the rate of strain recovery have been measured as a function of: applied shear rate, applied shear magnitude, temperature and molecular weight. The elastic properties indicate that there is an abrupt change or “transition” in the response of polystyrene melts at temperatures well above the glass transition. This abrupt change is found to be molecular weight dependent. The results are interpreted qualitatively in terms of molecular structure and practical processing operations. The possible relationship of this “transition” to Tu, is briefly discussed. |
