Elastic Losses in Some High Polymers as a Function of Frequency and Temperature

Abstract

The frequency and temperature dependence of the elastic losses of polyvinyl chlorides (0° to 80°C, 60 to 1400 c.p.s.) and of natural rubber and butadiene-styrene copolymers (GRS) of different relative concentration (−50° to 35°C, 20 to 3500 c.p.s.) was studied by 3 methods, in which the motion of a reed in free or forced vibration is observed. Natural rubber at temperatures above 20°C, and polyvinyl chloride exhibit frequency independent losses, the mechanism of which is not yet clear. The results for rubber below 20° and for GRS can be explained by a relaxation theory. The behavior of the elastic losses also reflects the existence of a second-order transition, below which rotation of chain segments is hampered.