Variation of dynamic mechanical properties of polycarbonate as a result of deformation

A combination of different experimental apprati has allowed dynamic mechanical spectroscopic measurements to be made as function of variable, constant offset stress, as well as during creep of bisphenol‐A‐polycarbonate. The deformation system was calibrated with aluminum and by comparison of low‐stress dynamic mechanical spectra with literature data of polycarbonate. Dynamic mechanical spectra acquired at high offset stress result in an apparent shift in sub‐Tg relaxation processes to higher temperatures at differing rates, resulting in separation of the various relaxation processes. This observed phenomenon is analogous to similar effects that are observed viathe application of pressure. The creep process can be clearly monitored by changes in dynamic mechanical properties, with these changes being dependent upon the stress and temperature utilized.