Enhancing thermal mechanical properties of polymer composites with hollow porous fillers

Abstract

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 SiO2 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 SiO2 counterparts. This approach offers a new avenue for enhancing the thermal mechanical properties of polymer composites.