Dynamical mechanical thermoanalysis of high performance reinforced materials - Influences and problems

A sensitive method to characterize the thermomechanical behaviour of fiber reinforced composites is the dynamic mechanical thermoanalysis (DMTA) metho d. A Round-Robin-test with five different institutes was conducted to deter mine the role of the fiber orientation, processing conditions, test apparat us, the mode of loading, and the matrix materials on the determination of t he glass transition temperature (T-g). The result shows that the DMTA is a suitable method to analyze T-g of long fiber composites. However, some majo r problems have to be taken into consideration: A direct comparison of results from different DMTA-systems is not possible The real temperatures in the specimens deviate from the temperatures displa yed by the DMTA measuring system There is no clear and common evaluation method for the glass transition tem perature.