Dynamical Mechanical Thermo Analysis of High Performance Composites-Influences and Problems

Abstract

A sensitive method to characterize the thermomechanical behavior of fiber reinforced composites is the dynamic mechanical thermo analysis (DMTA) method. A Round-Robin-Test with five different institutes was conducted to determine the role of the fiber orientation, processing conditions, test apparatus, mode of loading as well as the fiber and matrix materials on the determination of the glass transition temperature (T _g). The results show that the DMTA is a suitable method to analyze T _g of long fiber composites; however some major problems have to be taken into consideration. A direct comparison between the results obtained from different DMTA-systems is not possible since the real temperatures in the specimens deviated from the temperatures displayed by the DMTA measuring system. Therefore, no clear and common evaluation method for the glass transition temperature can be established. The significant influences on the T _g is proven by the performed statistical analysis.

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