A new approach for dynamic mechanical thermal analysis: The energy dissipation rate method

摘要

We report for the first time a new approach for analyzing the DMTA spectra of the internal friction of binary systems (polymer - additive) - the energy dissipation rate method. The method involves representation of the loss spectrum in the free damp oscillation (FDO) mode in the form: absorption coefficient alpha(nu) = Lambda(nu)*f(nu), where Lambda(nu) is logarithmic decrement of oscillation and f(nu) is frequency of free damp oscillation (nu approximate to 0,7T degrees K). The experimental data presented in these coordinates allows for: (1) correct application of all mathematical operations with the spectra alpha(nu), as with ordinary optical absorption spectra; (2) quantification of the individual components' contributions to the spectra of internal friction in multicomponent systems (composites, polymers with residual solvent, porous sorbents, glass forming systems and many others). The study investigated a model binary glass forming system made up of poly (vinyl-formal) - glycerol. The results of analysis of the loss spectra in FDO mode, associated with the additive (glycerol), correspond well to data received from far IR and dielectric spectroscopy of the dopant.