Comparison of similar narrow molecular weight polystyrenes

Abstract

Discrepancies between the level of the viscosity at 200°C of the Dow series of polystyrenes and another narrow molecular weight distribution polystyrenes have been pointed out by Toosi, Porter, and Johnson in 1969. Penwell and Graessley have shown in 1974 that over a wide range in temperature one member of this series, S109, has a significantly lower viscosity than samples of similar molecular weight from other sources. Fetters has established the presence of high molecular weight tails in several of the much studied series. The investigation being reported here reveals the effect of the high molecular weight tail in the viscoelastic behavior of the S109 in the terminal zone of response. In addition, it is shown by an enhanced rate of creep in the glass to rubber‐like dispersion that the glass temperature of the S109 is depressed by about 4°C.