Volume 4, Issue 3 (May 1976)
Characterization of Polymeric Materials by Dynamic Mechanical Properties
The determination and analysis of dynamic mechanical properties provide valuable information to characterize polymeric materials. Such testing of polymers with a torsional pendulum is a relatively simple procedure which requires a small amount of sample and is especially sensitive to changes in molecular structure. Thus, the dynamic mechanical properties of polymeric materials can be related directly to the composition, chemical structure, and morphology of the polymer chains. Data are presented which demonstrate the utility of dynamic mechanical properties in the evaluation of polymeric systems based on the presence of crystalline material, the addition of chemical crosslinks, the incorporation of a plasticizer, and copolymers or blends which exhibit various degrees of component compatibilities. The analytical characteristics of particular interest include the glass transition temperature(s) of the material, the occurrence of any secondary relaxations, and the relative change in modulus values and loss properties, all as functions of temperature and time.