Enhancing thermal mechanical properties of polymer composites with hollow porous fillers

Incorporating inorganic fillers is a common strategy for reducing the coefficient of thermal expansion (CTE) in polymers, but it is often associated with limited efficiency and a sacrifice in mechanical compliance. Current approaches mainly involve surface modification of fillers to overcome these challenges, but a significant proportion of fillers remain underutilized. In this study, we introduced hollow porous SiO 2 particles as fillers, utilizing both their external and internal surfaces to interact with the matrix. Moreover, the hollow porous structure allows the matrix to penetrate into the filler cavities, creating a unique mechanical interlock with the matrix. These combined effects result in a higher efficiency for CTE reduction and a significant improvement in the glass transition temperature. Furthermore, the hollow structure reduces the modulus of the fillers, resulting in a lower composite modulus compared to solid SiO 2 counterparts. This approach offers a new avenue for enhancing the thermal mechanical properties of polymer composites.