High-density polyethylene, its composites with hydrophilic/hydrophobic silica and the antioxidant BHT (butylated hydroxytoluene)
were studied using the thermogravimetric analysis. It has been shown that filling with silica as well as introducing BHT into
the unfilled polymer increases the thermal-oxidative stability of the polymer. Immobilized BHT is inactive and it suppresses
the stabilizing effect of hydrophobic silica surface in the processes of thermal oxidation at the initial stage. However,
being gradually released from the surface antioxidant prolongs the resistance of the polymer against oxidation.