Dual-Functional Silane Coupling Agents Synergistically Regulate Interfacial Interactions and Filler Dispersion in Hollow Glass Beads/PPESK Composites to Enhance Mechanical and Thermal Insulation Properties

To address the issue of interfacial compatibility between HGB and the high-performance resin PPESK, this study employed phenylsilane (PTES) and aminosilane (KH550) to perform synergistic surface modification of HGB. We systematically investigated the effects of different coupling agent ratios on interfacial structure, filler dispersion, and the mechanical and thermal insulation properties of the composites. The results show that the dual-coupling agent system achieves compatibility with the PPESK matrix by synergistically regulating the surface polarity of the filler. This approach enhances interfacial bonding while effectively suppressing filler agglomeration and fragmentation, with the optimal synergistic effect achieved at a KH550/PTES ratio of 4:6. Consequently, a synergistic improvement in both mechanical and thermal insulation properties was realized. Furthermore, the synergistic modification system also demonstrated significant advantages in terms of thermal stability, thermomechanical properties, and resistance to hydrothermal aging.