Atmospheric plasma torch treatment of polyethylene/boron composites: Effect on thermal stability

Low density polyethylene (LDPE) and its boron composites (LDPEB) are typically used as coatings with functional nuclear properties. However, they present low surface energy and adhesion problems. Atmospheric pressure plasma torch (APPT) processes improve polymer wettability. The main objective of this work is the evaluation of the effect of APPT on the thermal stability of LDPE and its composites reinforced with 15 and 30% (by wt.) of boron. Physical and chemical changes on the surface of treated materials are analysed using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The influence on thermal stability is evaluated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. The decomposition rate is measured by means of the Kamal equation, and the activation energy of the reaction is calculated from an Arrhenius equation and the Kissinger method. Results show that the APPT treatment is adequate to treat these materials (LDPE and its boron containing composites), as it does not degrade the material, but it modifies the chemistry and nanoroughness of the surface, increasing its wettability.