“Improvement in the energy dissipation capacity of polypropylene composites through a surface modification of titanium dioxide particles with a dicarboxylic acid”

In this work, we modified commercial TiO₂ nanoparticles using pimelic acid (PA) as an agent to improve interaction of titanium dioxide (TiO₂) into an isotactic polypropylene (iPP) matrix. The chemical bond of PA at the TiO₂ surface, allows a thermal and UV stabilization of PA molecules avoiding its decomposition in a process involving high temperature. As a consequence of an appropriate TiO2 integration into iPP, the results of the dynamical-mechanical analysis reveal that the iPP filled with modified particles (c-TiO₂) dissipate around two times more energy than those with the non-modified particles (n-TiO₂). A multi-frequency analysis of these composites also allowed us to estimate the apparent activation energy required to carry out the vitreous transition of these composites filled with c-TiO₂, which shows that particles are effectively well integrated with the iPP. These results validate the surface modification as an appropriate strategy to improve both, coloring capacity of TiO₂ and mechanical stress resistance of iPP measured as dissipated energy into the bulk of iPP with modified TiO₂ particles.