Cure Characteristics and Thermal Behavior of Organic-Inorganic Hybrid Composite as Assessed by DSC, TGA, and DMA Techniques

The current investigation reports the use of a residue from the iron metallurgy namely, slag to produce unsaturated polyester composite material-based slag (UPES). The slag has been mechanically treated by crushing and milling prior incorporating in the polymer. The role of the slag as co-curing agent of the polymerization reaction is studied under isothermal and dynamic conditions using differential scanning calorimeter (DSC); consequently, the role of the slag to enhance the thermal stability as well as the heat storage capacity of the UPE is reported. The isothermal cure temperature was varied from 80 to 120 degrees C, whereas the dynamic scan was run from room temperature to 250 degrees C at constant heating rate. This allowed us to estimate the degree of cure and cure rate. It has been found that incomplete cure was recorded by DSC for the pristine sample due to vitrification phenomenon. On the other hand, the sample with the slag displayed complete cure at 120 degrees C indicating that the heat storage capability of the polymer has been improved. The thermal stability of the samples was evaluated by a thermogravimetric analyzer coupled with a DSC unit. The sample containing slag responded better against thermal stimulation which was related to the mineral nature of the slag and the polar-polar interactions between the slag and the matrix. The interactions were attributed to the switch from hydroxyl-hydroxyl interactions to the formation of hydroxyl-slag (oxide). The interactions between the slag and the UPE resin were inspected using attenuated total reflectance infrared spectroscopy. The response of the samples to dynamic stimulation was evaluated by a dynamic mechanical analyzer. The sample containing slag displayed higher elastic moduli and broader tan (alpha) indicating better damping.