Effects of mesoporous silica coated multi-wall carbon nanotubes on the mechanical and thermal properties of epoxy nanocomposites

• We provide a simple method to prepare the mesoporous silica coated multi-wall carbon nanotubes by using sodium silicate as silica source and gelatin as surface-activation agent.
• In the presence of the polar silica shell, the CNTs@MS exhibited a more uniformed dispersion in epoxy-based nanocomposite than that of the CNTs.
• The uniform silica shell is benefit to give enhanced thermal conductivity and mechanical properties in the composites.

Mesoporous silica coated multi-wall carbon nanotubes (denoted as CNTs@MS) were prepared using sodium silicate as the silica source and gelatin as the surface-activation agent. The effects of CNTs@MS on the mechanical and thermal properties of epoxy composite are investigated in this study. The electron microscopy images and Fourier transform infrared spectra demonstrate integral coating of the mesoporous silica on the CNTs. Because of the polar silica shell, the CNTs@MS exhibited uniform dispersion in epoxy-based nanocomposite. The thermal and mechanical properties of nanocomposites were characterized using dynamic mechanical analysis (DMA), thermo-mechanical analysis (TMA) and thermal conductivity measurement. These results show that the storage modulus and thermal conductivity increased along with the amount of CNTs@MS (0.25, 0.5, 1.0 and 2.0 wt%). The coefficient of thermal expansion decreased gradually, because the dipole–dipole interactions between the silica and epoxy polymer and confinement space of the mesoporous structure reduced the thermal mobility of the epoxy polymer inside the mesopore space.