Significance and Use
5.1 Dynamic mechanical testing provides a method for determining elastic and loss moduli as a function of temperature, frequency or time, or both. A plot of the elastic modulus and loss modulus of material versus temperature provides a graphical representation of elasticity and damping as a function of temperature or frequency.
5.2 This procedure can be used to locate transition temperatures of plastics, that is, changes in the molecular motions of a polymer. In the temperature ranges where significant changes occur, elastic modulus decreases rapidly with increasing temperature (at constant or near constant frequency) or increases with increasing frequency (at constant temperature). A maximum is observed for the loss modulus, as well as for the tan delta curve, in the transition region.
5.6 Procedural modifications in material specifications take precedence to this practice. Therefore, consult the appropriate material specification before using this practice. Table 1 of Classification System D4000 lists the ASTM materials standards that currently exist.
1.1 This practice is for general use in gathering and reporting dynamic mechanical data. It incorporates laboratory practice for determining dynamic mechanical properties of plastic specimens subjected to various oscillatory deformations on a variety of instruments of the type commonly called dynamic mechanical analyzers or dynamic thermomechanical analyzers.
1.2 This practice is intended to provide means of determining the transition temperatures, elastic, and loss moduli of plastics over a range of temperatures, frequencies, or time, by free vibration and resonant or nonresonant forced vibration techniques. Plots of elastic and loss moduli are indicative of the viscoelastic characteristics of a plastic. These moduli are functions of temperature or frequency in plastics, and change rapidly at particular temperatures or frequencies. The regions of rapid moduli change are normally referred to as transition regions.
1.5 Discrepancies in results are known to arise when obtained under differing experimental conditions. Without changing the observed data, reporting in full (as described in this practice) the conditions under which the data were obtained will enable apparent differences observed in another study to be reconciled. An assumption of this technique is that testing is conducted in the region of linear viscoelastic behavior.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this practice to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 8.