Preparation of MPS (mercaptopropyltrimethoxysilane)-coated SiO2 nanoparticle and its effect on mechanical properties of surface treated SiO2/EVA nanocomposite

SiO₂ nanoparticles were synthesized from different three precursors, namely, TEOS (tetraethyl orthosilicate), sodium metasilicate and sodium silicate. First, SiO₂ nanoparticles were prepared by a controlled hydrolysis of TEOS. In another method, SiO₂nanoparticles were prepared by precipitation in an emulsion medium from sodium metasilicate and hydrochloric acid solution. Finally, SiO₂ nanoparticles were also synthesized from sodium silicate by an emulsion method. In this study, we concentrated on dispersion and compatibility between nanosized SiO₂ particles and EVA (ethylene vinyl acetate). Therefore, surface modification of synthesized SiO₂ nanoparticles was accomplished with MPS (3-mercaptopropyl trimethoxysilane) to enhance homogeneous dispersion and compatibility between the obtained SiO₂ nanoparticles and EVA. Finally, nanocomposites of surface treated SiO₂ nanoparticles and EVA were prepared. By inserting the MPS-coated SiO₂ nanoparticles into EVA, abrasion resistance and hardness were increased remarkably. On the other hand, insertion of SiO₂ nanoparticles barely decreased original tensile strength and elongation of EVA. Consequently, MPS-coated SiO₂/EVA nanocomposite can have an improved abrasion resistance and hardness compared with raw EVA, without decrease tensile strength and elongation. The characterization of synthesized SiO₂ nanoparticles and their nanocomposite with EVA was conducted by TEM, SEM, FTIR photography and mechanical property tests such as abrasion, hardness, tensile strength and elongation.