Morphology and thermal kinetics of electron beam irradiated polyetherimide/ polylactic acid (PEI/PLLA) blends

This research describes the effect of electron beam irradiation on the morphological properties and the thermal kinetics of polyetherimide/polylactic acid (PEI/PLLA) blends. We prepared blends based on different ratios by dissolving them in chloroform to form thin films through casting their solutions. These blend films were then subjected to the electron beam irradiation with the resulting films being thoroughly examined by various techniques including thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The thermal stability of the films was further investigated by the determination of the activation energy by two distinct approaches relying on the Broido and Coats-Redfern approximation equations. Based on weight loss and reaction rate, the thermogravimetric analysis (TGA) results showed that, adding up to 10 % of PLLA to the PEI/PLLA blends improved the thermal stability. The glass transition temperature (Tg) of PEI or PLLA was not revealed by the differential scanning calorimetry (DSC) scans; but DSC showed the existence of compatibility by revealing a new single glass transition.