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

Abstract

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.