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This paper explores the potential of Sample Controlled Thermal Analysis (SCTA) in order to perform compositional analysis of multicomponent polymeric materials by means of thermogravimetric experiments. In SCTA experiments, the response of the sample to the temperature determines the evolution of the temperature by means of a feedback system, thus, what is controlled is not the temperature-time profile as in conventional analysis, but rather the evolution of the reaction rate with time. The higher resolving power provided by the technique has been used for determining the composition of polymer blends composed of polyvinyl chloride (PVC) and different commercial plasticizers, a system where the individual components have very similar thermal stabilities, thereby rendering useless thermogravimetric experiments run under conventional conditions. Different SCTA procedures such as Constant Rate Thermal Analysis (CRTA), which has received special attention, Hi-Res and Stepwise Isothermal Analysis have been tested and the results obtained have been compared with linear heating rate technique. It has been proven that CRTA can be used to effectively determine the exact composition of the blend.

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The effect of ultraviolet radiation on styrene-ethylene-butadiene-styrene (SEBS) has been studied at different exposures times in order to obtain a better understanding of the mechanism of ageing. The polymer materials were mechanically tested and then their surfaces were analyzed using a scanning electron microscope (SEM) and atomic force microscopy (AFM). Moreover, the optical analysis of contact angle (OCA) was used to evaluate the surface energy (γ s ) and the yellowing index (YI) and attenuated total reflectance infrared spectroscopy (ATR-FTIR) were used to observe structural and physical changes in aging SEBS. The results obtained for the SEBS, in relation to the duration of exposure, showed superficial changes that cause a decrease in the surface energy (γ s ) and, therefore, a decrease in surface roughness. This led to a reduction in mechanical performance, decreasing the tensile strength by about 50% for exposure times of around 200 hours.