DYNAMIC MECHANICAL ANALYSIS OF POLYMERIC SYSTEMS IN LIQUID ENVIRONMENTS

Dynamic mechanical properties of polymer systems immersed in liquid environments have the potential of providing a wealth of characterization information relating to durability and performance characteristics of the material. However, when oscillatory experiments are performed in liquids, the effect of fluid drag on the sample and/or clamps must be subtracted from the data if the true material properties of the polymer are to be measured. Using classic dimensional analysis, a correlation was developed for calculating the friction of a sample/clamps combination in different liquids in relation to a Reynolds number defined for the immersed system. The methodology was adapted to the DuPont DMA using a poly(tetrafluoroethylene) (PTFE) polymer sheet to avoid any liquid sorption by the sample. It was found that storage and loss friction parameters could be determined and subtracted from the measured data to provide fluid-independent dynamic mechanical properties for the sample.