Thermal kinetics and compatibilization of polyethylene / polystyrene blend with the addition of inorganic particles

In this dissertation, the melting behavior and thermal properties of polystyrene (PS) and polyethylene (PE) were evaluated. It was noticed that titanium dioxide (TiO₂) particles have unique function to modify the crystalline structure and the interactions between particles and polymer chains. In addition, the compatibility of PE/PS blends was improved with the help of inorganic particles addition. First, the effect of interactions and possibly the free-volume confinement of chains were probed on PE thin films. Experiment results shown that while adding TiO₂ decreased the melting temperature of thin PE films and the ZnSe had an inverse effect, which indicated that interaction between particles and polymer interface was the dominant factor of polymer thermal behavior. Second, focused on the observation of glass transition temperature (T_g) of PS, it was asserted that the addition of TiO₂ would result in a distinct change in T_g which was attributed to the interactions between substrate particles and polymer chains. Based on these precursor results, the effect of TiO₂ on crystalline behavior and thermal kinetics of PE/PS blend were examined by differential scanning calorimetry (DSC), Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The improved compatibility of the two immiscible polymers was confirmed by creep resistance experiment as well.