INFLUENCE OF SILICA NANOPARTICLES ON THE THERMOMECHANICAL PROPERTIES OF RECYCLED POLYSTYRENE

Polystyrene from packing materials (rPS) was reinforced with 1, 3 and 5 % of silica prepared by the sal-gel method, through a blending process. The thermal, morphological and mechanical properties were compared with those of the virgin polystyrene (PS). The results show that the glass transition temperature (Tg), storage modulus (E') and impact strength of the pure rPS and silica-rPS composites were higher than those of virgin PS. Thermogravimetric analysis revealed that the thermal stability of virgin PS was slightly greater than that of the rPS. The addition of silica to rPS increased their thermal stability to similar values of the virgin PS. SEM studies showed that the silica nanoparticles had an uniform size but its dispersion into the polymer matrix was not homogeneous. These results suggest that postconsumer PS can be used to obtain composite materials with good mechanical and thermal properties.