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.