Monitoring Thermal Transformations in Hybrid Composites

Hybrid composites, mixtures of organic and inorganic materials frequently achieve their final properties after thermal treatment involving partial or complete decomposition and chemical reactions. Three examples are presented to demonstrate the possibilities of monitoring these complex transformations by various analytical techniques. The first one is a polyurea based prepreg system containing both organic and inorganic additives, achieving extreme heat stability after curing followed by a heat treatment. Next example is taken from alumina based ceramic injection molding systems. The effects of matrix polymer and various additives, such as citric acid, UHMWPE (ultrahigh molecular weight polyethylene) and the effect of alumina trihydrate/alumina ratio in the ceramic injection molding feedstock was studied on the processability and porosity. The last example presents a new approach to prepare ODS (oxide dispersed steel) bodies by using metalorganic compounds as additives in metal injection molding feedstocks. Applied characterization methods included thermogravimetry (TGA), differential thermal analysis (DTA), X-ray diffraction (WAXS), X-ray photoelectron spectroscopy (XPS), scanning electron microcopy (SEM) coupled with energy dispersive X-ray analysis (EDX), vibrational spectroscopy (Raman and FTIR) and density measurements.