Synthesis and modification of spherical SiO₂ nanoparticles with different particle sizes and morphologies and their effects on the properties of thermoplastic polyurethane urea elastomers

Abstract

A thermoplastic polyurethane urea (TPUU) elastomer with superior mechanical and thermal properties was recently reported from our group and synthesized by asymmetric aliphatic diisocyanate and diamine. In order to enhance its performance, this TPUU was further modified with spherical SiO 2 nanoparticles in this work, and the influence of the size and morphology of spherical SiO 2 nanoparticles on mechanical, thermal, and thermomechanical properties of TPUU was investigated. The results showed that spherical SiO 2 nanoparticles could significantly improve the mechanical, thermal, and thermomechanical properties of TPUU, which increased, with the decrease of the particle size of SiO 2 nanoparticles. Especially, compared with solid spherical SiO 2 nanoparticles, TPUU nanocomposites filled with hollow spherical SiO 2 (HSSiO 2 ) particles showed abnormal but unique stress-strain behavior, and their elongations at break increased with the decrease of particle size of HSSiO 2 nanoparticles. K E Y W O R D Smechanical property, solid/hollow spherical SiO 2 nanoparticles, thermomechanical property, thermoplastic polyurethane urea (TPUU) elastomer