Investigation of Synergistic Existence Effect of SiO2 and TiO2 Nanoparticles in Polystyrene Nanocomposite and Comparison of their Mechanical and Thermal Properties

In this research, mechanical properties improvement such as elongation at break and young modulus of polystyrene (PS) was investigated in presence of TiO2 and SiO2 nanoparticles. The solution method was selected for synthesis of PS/SiO2, PS/TiO2 and PS/SiO2/TiO2 nanocomposite. An ultrasonic mixer was used for higher dispersion of nanoparticle in the solvent. Morphology of produced samples was characterized through SEM, TEM and TGA. The mechanical properties of nanocomposites were studied by determination of young modulus, elongation at break and impact strength. The results showed that the elongation at break of PS is obviously enhanced in presence of both TiO2 and SiO2 nanoparticles. Also, the results indicated that in the PS/SiO2/TiO2 sample with 1 wt.% of nanoparticles, young modulus, fracture toughness and elongation at break of PS are increased simultaneously. This phenomenon was due to good breakdown structure of nanoparticles agglomeration, and also sufficient dispersion of them in PS matrix. In this case, the nanoparticles were filled in fine voids and played a roll of bridge between layers of matrix leading to improvement of elongation at break of PS. Also, thermal stability was developed in comparison with unfilled PS due to well-structural homogeneity and reduction of defected sites numbers.