Structural, dynamic mechanical and dielectric properties of mesoporous silica/epoxy resin nanocomposites

Research of mesoporous silica/polymer composite indicated that the mechanical property and thermal stability of the composite were remarkably enhanced due to the effective utilization of nanopore specific surface area. Furthermore, the performance of the mesoporous silica/polymer under a high electric field was promising. In this work, an organic-inorganic hybrid structure composed of mesoporous silica (SBA-15) and epoxy resin was prepared. The silane coupling agent, KH550, was used to enhance the interaction between the particles and the epoxy molecules, and the particles were more evenly dispersed in the polymer matrix. Nitrogen adsorption-desorption and Fourier transform infrared spectroscopy experiments showed that the KH550 molecules spread into the nanopores, and reacted with the hydroxyl group of the SBA-15 particles. The transmission electron microscopy analysis for the composites showed that the epoxy was inserted into the nanopores of SBA-15, and an organic-inorganic hybrid structure composite was formed. The dynamic mechanical and dielectric properties of the composite were studied. The storage modulus at 120°C, glass transition temperature, and AC breakdown strength for 0.3 wt% SBA-15-KH550/epoxy composite were 1784 MPa, 148.2°C, and 56.2 kV/mm, increased 1241%, 14%, and 73% compared to those of pure epoxy, respectively. Moreover, the permittivity for the 0.3 wt% SBA-15-KH550/epoxy composite decreased from 3.10 (pure epoxy) to 2.73 due to the voids provided by the unfilled nanopores and the improved interfacial interaction between the SBA-15 and the epoxy.